loncom/interface/statistics/lonproblemstatistics.pm - diff

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Diff for /loncom/interface/statistics/lonproblemstatistics.pm between versions 1.41 and 1.122.2.3

-version 1.41, 2003/03/25 23:00:40
+version 1.122.2.3, 2014/03/03 20:45:05
  Line 26
  #
  # (Navigate problems for statistical reports
  #
- ###
+ ###############################################
+ ###############################################
- package Apache::lonproblemstatistics;
- use strict;
+ =pod
- use Apache::lonnet();
- use Apache::lonhtmlcommon;
- use Apache::loncoursedata;
- use Apache::lonstatistics;
- #######################################################
+ =head1 NAME
- #######################################################
- sub CreateInterface {
+ lonproblemstatistics
-     my $Str = '';
-     $Str .= '<table cellspacing="5">'."\n";
-     $Str .= '<tr>';
-     $Str .= '<td align="center"><b>Sections</b></td>';
-     $Str .= '<td align="center"><b>Sequences and Folders</b></td>';
-     $Str .= '<td align="center"><b>Output</b></td>';
-     $Str .= '</tr>'."\n";
-     #
-     $Str .= '<tr><td align="center">'."\n";
-     $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
-     $Str .= '</td><td align="center">';
-     #
-     my $only_seq_with_assessments = sub {
-         my $s=shift;
-         if ($s->{'num_assess'} < 1) {
-             return 0;
-         } else {
-             return 1;
-         }
-     };
-     $Str .= &Apache::lonstatistics::MapSelect('Maps','multiple,all',5,
-                                               $only_seq_with_assessments);
-     $Str .= '</td><td>'."\n";
-     $Str .= &CreateAndParseOutputSelector();
-     $Str .= '</td></tr>'."\n";
-     $Str .= '</table>'."\n";
-     return $Str;
- }
- #######################################################
+ =head1 SYNOPSIS
- #######################################################
- =pod
+ Routines to present problem statistics to instructors via tables,
+ Excel files, and plots.
- =item &CreateAndParseOutputSelector()
+ =over 4
  =cut
- #######################################################
+ ###############################################
- #######################################################
+ ###############################################
- my $output_mode;
- my $show;
- my @OutputOptions =
-     (
-      { name  => 'problem statistics grouped by sequence',
-        value => 'HTML problem statistics grouped',
-        description => 'Output statistics for the problem parts.',
-        mode => 'html',
-        show => 'grouped',
-      },
-      { name  => 'problem statistics ungrouped',
-        value => 'HTML problem statistics ungrouped',
-        description => 'Output statistics for the problem parts.',
-        mode => 'html',
-        show => 'ungrouped',
-      },
-      { name  => 'problem statistics, Excel',
-        value => 'Excel problem statistics',
-        description => 'Output statistics for the problem parts '.
-            'in an Excel workbook',
-        mode => 'excel',
-        show => 'all',
-      },
-      { name  => 'Degree of Difficulty Plot',
-        value => 'plot deg diff',
-        description => 'Generate a plot of the degree of difficulty of each '.
-            'problem part.',
-        mode => 'plot',
-        show => 'deg of diff',
-      },
-      { name  => 'Percent Wrong Plot',
-        value => 'plot per wrong',
-        description => 'Generate a plot showing the percent of students who '.
-            'were unable to complete each problem part',
-        mode => 'plot',
-        show => 'per wrong',
-      },
-      );
- sub OutputDescriptions {
+ package Apache::lonproblemstatistics;
-     my $Str = '';
-     $Str .= "<h2>Output Modes</h2>\n";
-     $Str .= "<dl>\n";
-     foreach my $outputmode (@OutputOptions) {
- 	$Str .="    <dt>".$outputmode->{'name'}."</dt>\n";
- 	$Str .="        <dd>".$outputmode->{'description'}."</dd>\n";
-     }
-     $Str .= "</dl>\n";
-     return $Str;
- }
- sub CreateAndParseOutputSelector {
+ use strict;
-     my $Str = '';
+ use Apache::lonnet;
-     my $elementname = 'outputmode';
+ use Apache::loncommon();
+ use Apache::lonhtmlcommon;
+ use Apache::loncoursedata;
+ use Apache::lonstatistics;
+ use LONCAPA::lonmetadata();
+ use Apache::lonlocal;
+ use Spreadsheet::WriteExcel;
+ use Apache::lonstathelpers();
+ use Time::HiRes;
+ use LONCAPA;
+ my @StatsArray;
+ my %SeqStat;    # keys are symbs, values are hash refs
+ ##
+ ## Localization notes:
+ ##
+ ## in @Fields[0]->{'long_title'} is placed in Excel files and is used as the
+ ## header for plots created with Graph.pm, both of which more than likely do
+ ## not support localization.
+ ##
+ ## Additional Notes:
+ ## Localization can be done and is done before passing the phrases
+ ## to the output.
+ ## This might conflict with special characters, e.g. German Umlaute or
+ ## chinese characters. Do not use such characters in this case.
+ ## If this failed, consider that the sequence and folder names
+ ## are also passed to the output and would fail the same way.
+ ##
+ #
+ #
+ ##
+ ## Description of Field attributes
+ ##
+ ## Attribute     Required   Value       Meaning or Use
+ ##
+ ## name            yes      any scalar  Used to uniquely identify field
+ ## title           yes      any scalar  This is what the user sees to identify
+ ##                                      the field.  Passed through &mt().
+ ## long_title      yes      any scalar  Used as graph heading and in excel
+ ##                                      output.  Passed through &mt().
+ ## align           no    (left|right|center)  HTML cell contents alignment
+ ## color           yes      html color  HTML cell background color
+ ##                                      used to visually group statistics
+ ## special         no          (link)   Indicates a link, target is name.link
+ ##                                      Currently set in &get_statistics()
+ ## graphable       no      (yes|no)     Can a bar graph of the field be
+ ##                                      produced?
+ ## sortable        no      (yes|no)     Should a sort link be put in the
+ ##                                      column header?
+ ## selectable      yes     (yes|no)     Can the column be removed from the
+ ##                                      statistics display?
+ ## selected        yes     (yes|no)     Is the column selected by default?
+ ##
+ ## format          no      sprintf format string
+ ##
+ ## excel_format    no      excel format type
+ ##                               (see &Apache::loncommon::define_excel_formats
+ my @Fields = (
+            { name => 'problem_num',
+              title => 'P#',
+              align => 'right',
+              color => '#FFFFE6',
+              selectable => 'no',
+              defaultselected => 'yes',
+            },
+            { name   => 'container',
+              title  => 'Sequence or Folder',
+              align  => 'left',
+              color  => '#FFFFE6',
+              sortable => 'yes',
+              selectable => 'no',
+              defaultselected => 'yes',
+            },
+            { name   => 'title',
+              title  => 'Title',
+              align  => 'left',
+              color  => '#FFFFE6',
+              special  => 'link',
+              sortable => 'yes',
+              selectable => 'no',
+              defaultselected => 'yes',
+            },
+            { name   => 'part',
+              title  => 'Part',
+              align  => 'left',
+              color  => '#FFFFE6',
+              selectable => 'no',
+              defaultselected => 'yes',
+            },
+            { name   => 'num_students',
+              title  => '#Stdnts',
+              align  => 'right',
+              color  => '#EEFFCC',
+              format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Number of Students Attempting Problem',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'tries',
+              title  => 'Tries',
+              align  => 'right',
+              color  => '#EEFFCC',
+              format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Total Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'max_tries',
+              title  => 'Max Tries',
+              align  => 'right',
+              color  => '#DDFFFF',
+              format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Maximum Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'min_tries',
+              title  => 'Min Tries',
+              align  => 'right',
+              color  => '#DDFFFF',
+              format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Minimum Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'mean_tries',
+              title  => 'Mean Tries',
+              align  => 'right',
+              color  => '#DDFFFF',
+              format => '%5.2f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Average Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'std_tries',
+              title  => 'S.D. tries',
+              align  => 'right',
+              color  => '#DDFFFF',
+              format => '%5.2f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Standard Deviation of Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'skew_tries',
+              title  => 'Skew Tries',
+              align  => 'right',
+              color  => '#DDFFFF',
+              format => '%5.2f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Skew of Number of Tries',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'num_solved',
+              title  => '#YES',
+              align  => 'right',
+              color  => '#FFDDDD',
+              format => '%4.1f',#             format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Number of Students able to Solve',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'num_override',
+              title  => '#yes',
+              align  => 'right',
+              color  => '#FFDDDD',
+              format => '%4.1f',#             format => '%d',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Number of Students given Override',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'tries_per_correct',
+              title  => 'tries/correct',
+              align  => 'right',
+              color  => '#FFDDDD',
+              format => '%4.1f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Tries per Correct Answer',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'num_wrong',
+              title  => '#Wrng',
+              align  => 'right',
+              color  => '#FFDDDD',
+              format => '%4.1f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Number of students whose final answer is wrong',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'per_wrong',
+              title  => '%Wrng',
+              align  => 'right',
+              color  => '#FFDDDD',
+              format => '%4.1f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Percent of students whose final answer is wrong',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'deg_of_diff',
+              title  => 'DoDiff',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%5.2f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Degree of Difficulty'.
+                            ' ~[ 1 - ((#YES+#yes) / Tries) ~]',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+            { name   => 'deg_of_disc',
+              title  => 'DoDisc',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4.2f',
+              sortable  => 'yes',
+              graphable => 'yes',
+              long_title => 'Degree of Discrimination',
+              selectable => 'yes',
+              defaultselected => 'yes',
+            },
+ ##   duedate included for research purposes.  Commented out most of the time.
+ #           { name => 'duedate',
+ #             title => 'Due Date',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'yes',
+ #             graphable => 'no',
+ #             long_title => 'Due date of resource for instructor',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ ##   opendate included for research purposes.  Commented out most of the time.
+ #           { name => 'opendate',
+ #             title => 'Open Date',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'yes',
+ #             graphable => 'no',
+ #             long_title => 'date resource became answerable',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ ##   symb included for research purposes.  Commented out most of the time.
+ #           { name => 'symb',
+ #             title => 'Symb',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'yes',
+ #             graphable => 'no',
+ #             long_title => 'Unique LON-CAPA identifier for problem',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ ##   resptypes included for research purposes.  Commented out most of the time.
+ #           { name => 'resptypes',
+ #             title => 'Response Types',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'no',
+ #             graphable => 'no',
+ #             long_title => 'Response Types used in this problem',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ ##   maxtries included for research purposes.  Commented out most of the time.
+ #           { name => 'maxtries',
+ #             title => 'Maxtries',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'no',
+ #             graphable => 'no',
+ #             long_title => 'Maximum number of tries',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ ##   hinttries included for research purposes.  Commented out most of the time.
+ #           { name => 'hinttries',
+ #             title => 'hinttries',
+ #             align => 'left',
+ #             color => '#FFFFFF',
+ #             sortable => 'no',
+ #             graphable => 'no',
+ #             long_title => 'Number of tries before a hint appears',
+ #             selectable => 'no',
+ #             defaultselected => 'yes',
+ #            },
+ #
+ ##   problem weight for instructor
+            { name => 'weight',
+              title => 'weight',
+              align => 'right',
+              color => '#FFFFFF',
+              sortable => 'no',
+              graphable => 'no',
+              long_title => 'Problem weight (for instructor)',
+              selectable => 'yes',
+              defaultselected => 'yes',
+             },
+ );
+ my @SeqFields = (
+            { name   => 'title',
+              title  => 'Sequence',
+              align  => 'left',
+              color  => '#FFFFE6',
+              special  => 'no',
+              sortable => 'no',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'items',
+              title  => '#Items',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4d',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Number of Items in Sequence',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'scoremean',
+              title  => 'Score Mean',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Mean Sequence Score',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'scorestd',
+              title  => 'Score STD',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Standard Deviation of Sequence Scores',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'scoremax',
+              title  => 'Score Max',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Maximum Sequence Score',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'scoremin',
+              title  => 'Score Min',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Minimum Sequence Score',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'scorecount',
+              title  => 'Score N',
+              align  => 'right',
+              color  => '#FFFFE6',
+              format => '%4d',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Number of Students in score computations',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'countmean',
+              title  => 'Count Mean',
+              align  => 'right',
+              color  => '#FFFFFF',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Mean Sequence Score',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'countstd',
+              title  => 'Count STD',
+              align  => 'right',
+              color  => '#FFFFFF',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Standard Deviation of Sequence Scores',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'countmax',
+              title  => 'Count Max',
+              align  => 'right',
+              color  => '#FFFFFF',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Maximum Number of Correct Problems',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'countmin',
+              title  => 'Count Min',
+              align  => 'right',
+              color  => '#FFFFFF',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Minimum Number of Correct Problems',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'count',
+              title  => 'Count N',
+              align  => 'right',
+              color  => '#FFFFFF',
+              format => '%4d',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'Number of Students in score computations',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+            { name   => 'KR-21',
+              title  => 'KR-21',
+              align  => 'right',
+              color  => '#FFAAAA',
+              format => '%4.2f',
+              sortable  => 'no',
+              graphable => 'no',
+              long_title => 'KR-21 reliability statistic',
+              selectable => 'yes',
+              defaultselected => 'no',
+            },
+ );
+ my %SelectedFields;
+ sub parse_field_selection {
+     #
+     # Pull out the defaults
+     if (! defined($env{'form.fieldselections'})) {
+         $env{'form.fieldselections'} = [];
+         foreach my $field (@Fields) {
+             next if ($field->{'selectable'} ne 'yes');
+             if ($field->{'defaultselected'} eq 'yes') {
+                 push(@{$env{'form.fieldselections'}},$field->{'name'});
+             }
+         }
+     }
      #
-     # Format for output options is 'mode, restrictions';
+     # Make sure the data we are plotting is there
-     my $selected = 'html, with links';
+     my %NeededFields;
-     if (exists($ENV{'form.'.$elementname})) {
+     if (exists($env{'form.plot'}) && $env{'form.plot'} ne '' &&
-         if (ref($ENV{'form.'.$elementname} eq 'ARRAY')) {
+         $env{'form.plot'} ne 'none') {
-             $selected = $ENV{'form.'.$elementname}->[0];
+         if ($env{'form.plot'} eq 'degrees') {
+             $NeededFields{'deg_of_diff'}++;
+             $NeededFields{'deg_of_disc'}++;
+         } elsif ($env{'form.plot'} eq 'tries statistics') {
+             $NeededFields{'mean_tries'}++;
+             $NeededFields{'std_tries'}++;
+             $NeededFields{'problem_num'}++;
          } else {
-             $selected = $ENV{'form.'.$elementname};
+             $NeededFields{$env{'form.plot'}}++;
          }
      }
      #
-     # Set package variables describing output mode
+     # This should not happen, but in case it does...
-     $output_mode = 'html';
+     if (ref($env{'form.fieldselections'}) ne 'ARRAY') {
-     $show        = 'all';
+         $env{'form.fieldselections'} = [$env{'form.fieldselections'}];
-     foreach my $option (@OutputOptions) {
+     }
-         next if ($option->{'value'} ne $selected);
+     #
-         $output_mode = $option->{'mode'};
+     # Set the field data and the selected fields (for easier checking)
-         $show        = $option->{'show'};
+     undef(%SelectedFields);
+     foreach my $field (@Fields) {
+         if ($field->{'selectable'} ne 'yes') {
+             $field->{'selected'} = 'yes';
+         } else {
+             $field->{'selected'} = 'no';
+         }
+         if (exists($NeededFields{$field->{'name'}})) {
+             $field->{'selected'} = 'yes';
+             $SelectedFields{$field->{'name'}}++;
+         }
+         foreach my $selection (@{$env{'form.fieldselections'}}) {
+             if ($selection eq $field->{'name'} || $selection eq 'all') {
+                 $field->{'selected'} = 'yes';
+                 $SelectedFields{$field->{'name'}}++;
+             }
+         }
      }
      #
-     # Build the form element
+     # Always show all the sequence statistics (for now)
-     $Str = qq/<select size="5" name="$elementname">/;
+     foreach my $field (@SeqFields) {
-     foreach my $option (@OutputOptions) {
+         $field->{'selected'} = 'yes';
-         $Str .= "\n".'    <option value="'.$option->{'value'}.'"';
-         $Str .= " selected " if ($option->{'value'} eq $selected);
-         $Str .= ">".$option->{'name'}."<\/option>";
      }
-     $Str .= "\n</select>";
+     return;
-     return $Str;
+ }
+ sub field_selection_input {
+     my $Str = '<select name="fieldselections" multiple="multiple" size="5">'."\n";
+     $Str .= '<option value="all">'.&mt('all').'</option>'."\n";
+     foreach my $field (@Fields) {
+         next if ($field->{'selectable'} ne 'yes');
+         $Str .= '    <option value="'.$field->{'name'}.'"';
+         if ($field->{'selected'} eq 'yes') {
+             $Str .= ' selected="selected"';
+         }
+         $Str .= '>'.&mt($field->{'title'}).'</option>'."\n";
+     }
+     $Str .= "</select>\n";
  }
  ###############################################
  ###############################################
+ =pod
+ =item &CreateInterface()
+ Create the main intereface for the statistics page.  Allows the user to
+ select sections, maps, and output.
+ =cut
  ###############################################
  ###############################################
- sub Gather_Student_Data {
+ sub CreateInterface {
      my ($r) = @_;
-     my $c = $r->connection();
      #
-     my @Sequences = &Apache::lonstatistics::Sequences_with_Assess();
+     &parse_field_selection();
      #
-     my @Students = @Apache::lonstatistics::Students;
+     my $Str = '';
+     $Str .= &Apache::loncommon::start_data_table();
+     $Str .= &Apache::loncommon::start_data_table_header_row();
+     $Str .= '<th>'.&mt('Sections').'</th>';
+     $Str .= '<th>'.&mt('Groups').'</th>';
+     $Str .= '<th>'.&mt('Access Status').'</th>';
+     $Str .= '<th>'.&mt('Sequences and Folders').'</th>';
+     $Str .= '<th>'.&mt('Statistics').'</th>';
+     $Str .= '<th>'.&mt('Plot Graph').'</th>';
+     $Str .= '<th>'.&mt('Time Period').'</th>';
+     $Str .= &Apache::loncommon::end_data_table_header_row();
      #
-     # Open the progress window
+     $Str .= &Apache::loncommon::start_data_table_row();
-     my %prog_state=&Apache::lonhtmlcommon::Create_PrgWin
+     $Str .= '<td align="center" valign="top">'."\n";
-         ($r,'Statistics Compilation Status',
+     $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
-          'Statistics Compilation Progress', scalar(@Students));
+     $Str .= '</td><td align="center" valign="top">';
-     #
+     $Str .= &Apache::lonstatistics::GroupSelect('Group','multiple',5);
-     while (my $student = shift @Students) {
+     $Str .= '</td><td align="center" valign="top">';
-         return if ($c->aborted());
+     $Str .= &Apache::lonhtmlcommon::StatusOptions(undef,undef,5);
-         my ($status,undef) = &Apache::loncoursedata::ensure_current_data
+     $Str .= '</td><td align="center" valign="top">';
-             ($student->{'username'},$student->{'domain'},
+     #
-              $ENV{'request.course.id'});
+     $Str .= &Apache::lonstatistics::map_select('Maps','multiple,all',5);
-         &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,
+     $Str .= '</td><td align="center" valign="top">';
-                                                  'last student');
+     $Str .= &field_selection_input();
-     }
+     $Str .= '</td><td align="center" valign="top">';
-     &Apache::lonhtmlcommon::Close_PrgWin($r,\%prog_state);
+     $Str .= &plot_dropdown();
-     $r->rflush();
+     $Str .= "\n";
+     $Str .= '</td><td align="center" valign="top">';
+     $Str .= &Apache::lonstathelpers::limit_by_time_form();
+     $Str .= '</td>'."\n";
+     $Str .=  &Apache::loncommon::end_data_table_row();
+     $Str .= &Apache::loncommon::end_data_table();
+     #
+     $Str .= '<input type="submit" name="GenerateStatistics" value="'.
+         &mt('Generate Statistics').'" />';
+     $Str .= ('&nbsp;'x10);
+     #
+     return $Str;
  }
  ###############################################
  ###############################################
+ =pod
+ =item &BuildProblemStatisticsPage()
+ Main interface to problem statistics.
+ =cut
  ###############################################
  ###############################################
+ my $navmap;
+ my @sequences;
+ sub clean_up {
+     undef($navmap);
+     undef(@sequences);
+ }
  sub BuildProblemStatisticsPage {
      my ($r,$c)=@_;
+     undef($navmap);
+     undef(@sequences);
+     #
+     my %Saveable_Parameters = ('Status' => 'scalar',
+                                'statsoutputmode' => 'scalar',
+                                'Section' => 'array',
+                                'Groups' => 'array',
+                                'StudentData' => 'array',
+                                'Maps' => 'array',
+                                'fieldselections'=> 'array');
+     &Apache::loncommon::store_course_settings('statistics',
+                                               \%Saveable_Parameters);
+     &Apache::loncommon::restore_course_settings('statistics',
+                                                 \%Saveable_Parameters);
      #
-     $output_mode = 'html';
+     &Apache::lonstatistics::PrepareClasslist();
-     $show = 'grouped';
      #
-     $r->print(&CreateInterface());
+     # Clear the package variables
-     $r->print('<input type="hidden" name="statsfirstcall" value="no" />');
+     undef(@StatsArray);
-     $r->print('<input type="hidden" name="sortby" value="'.$ENV{'form.sortby'}.
+     undef(%SeqStat);
+     #
+     # Finally let the user know we are here
+     $r->print(&Apache::lonhtmlcommon::breadcrumbs('Overall Problem Statistics',
+                                                 'Statistics_Overall_Key'));
+     my $interface = &CreateInterface($r);
+     $r->print($interface);
+     $r->print('<input type="hidden" name="sortby" value="'.$env{'form.sortby'}.
                '" />');
-     if (! exists($ENV{'form.statsfirstcall'})) {
+     #
-         return;
+     my @CacheButtonHTML =
+         &Apache::lonstathelpers::manage_caches($r,'Statistics','stats_status');
+     my $Str;
+     foreach my $html (@CacheButtonHTML) {
+         $Str.=$html.('&nbsp;'x5);
      }
      #
-     &Gather_Student_Data($r);
+     $r->print($Str);
+     if (! exists($env{'form.firstrun'})) {
+         $r->print('<p class="LC_info"><b>'.
+                   &mt('Press "Generate Statistics" when you are ready.').
+                   '</b></p>'.
+                   '<p class="LC_info">'.
+                   &mt('It may take some time to update the student data '.
+                       'for the first analysis. Future analysis this session '.
+                       'will not have this delay.').
+                   '</p>');
+ 	&clean_up();
+         return;
+     }
+     $r->rflush();
      #
+     # This probably does not need to be done each time we are called, but
+     # it does not slow things down noticably.
+     &Apache::loncoursedata::populate_weight_table();
      #
-     if ($output_mode eq 'html') {
+     ($navmap,@sequences) =
-         $r->print("<h2>".
+         &Apache::lonstatistics::selected_sequences_with_assessments();
-                   $ENV{'course.'.$ENV{'request.course.id'}.'.description'}.
+     if (! ref($navmap)) {
-                   "</h2>\n");
+         $r->print('<div class="LC_error">'.&mt('A course-wide error occurred.').'</div>'.
-         $r->print("<h3>".localtime(time)."</h3>");
+                   '<h3>'.$navmap.'</h3>');
+ 	&clean_up();
+         return;
+     }
+     if (exists($env{'form.Excel'})) {
+         $r->print('<p>'.
+                   &Apache::lonstatistics::section_and_enrollment_description().
+                   '</p>');
+         &Excel_output($r);
+     } else {
+         $r->print('<input type="submit" name="Excel" value="'.
+                   &mt('Produce Excel Output').'" />'.'&nbsp;'x5);
          $r->rflush();
-         if ($show eq 'grouped') {
+         $r->print('<p>'.
-             &output_html_grouped_by_sequence($r);
+                   &Apache::lonstatistics::section_and_enrollment_description().
-         } elsif ($show eq 'ungrouped') {
+                   '</p>');
-             &output_html_ungrouped($r);
+         my $count = 0;
+         foreach my $seq (@sequences) {
+             my @resources =
+                 &Apache::lonstathelpers::get_resources($navmap,$seq);
+             $count += scalar(@resources);
+         }
+         if ($count > 10) {
+             $r->print('<p>'.
+                       &mt('Compiling statistics for [quant,_1,problem]',$count).
+                       '</p>');
+             if ($count > 30) {
+                 $r->print('<p class="LC_info">'.&mt('This will take some time.').'</p>');
+             }
+             $r->rflush();
+         }
+         #
+         my $sortby = $env{'form.sortby'};
+         $sortby = 'container' if (! defined($sortby) || $sortby =~ /^\s*$/);
+         my $plot = $env{'form.plot'};
+         if ($plot eq '' || $plot eq 'none') {
+             undef($plot);
+         }
+         if ($sortby eq 'container' && ! defined($plot)) {
+             &output_sequence_statistics($r);
+             &output_html_by_sequence($r);
+         } else {
+             if (defined($plot)) {
+                 &make_plot($r,$plot);
+             }
+             &output_html_stats($r);
+             &output_sequence_statistics($r);
          }
-     } else {
-         $r->print("<h1>Not implemented</h1>");
      }
+     &clean_up();
      return;
  }
- sub output_html_grouped_by_sequence {
+ sub output_sequence_statistics {
      my ($r) = @_;
-     #$r->print(&ProblemStatisticsLegend());
+     my $c=$r->connection();
-     my @Header = ("Title","Part","#Stdnts","Tries","Mod",
+     $r->print('<h2>'.&mt('Sequence Statistics').
-                   "Mean","#YES","#yes","%Wrng","DoDiff",
+ 	      &Apache::loncommon::help_open_topic('Statistics_Sequence').
-                   "S.D.","Skew.");#,"D.F.1st","D.F.2nd");
+ 	      '</h2>');
-     # #FFFFE6 #EEFFCC #DDFFFF FFDDDD #DDFFDD #FFDDFF
+     $r->print(&Apache::loncommon::start_data_table());
-     foreach my $sequence (&Apache::lonstatistics::Sequences_with_Assess()) {
+     $r->print(&sequence_html_header());
-         next if ($sequence->{'num_assess'}<1);
+     foreach my $seq (@sequences) {
-         $r->print("<h3>".$sequence->{'title'}."</h3>");
+         last if ($c->aborted);
-         $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+         &compute_sequence_statistics($seq);
-         $r->print('<table border="0" cellpadding="3">'."\n");
+         $r->print(&sequence_html_output($seq));
-         $r->print('<tr bgcolor="#FFFFE6"><th>'.
+     }
-                   join("</th><th>",@Header)."</th></tr>\n");
+     $r->print(&Apache::loncommon::end_data_table());
-         foreach my $resource (@{$sequence->{'contents'}}) {
+     $r->rflush();
-             next if ($resource->{'type'} ne 'assessment');
+     return;
-             foreach my $part (@{$resource->{'parts'}}) {
+ }
-                 if ($part == 0) {
-                     $part = '&nbsp;';
-                 }
+ ##########################################################
-                 my ($num,$tries,$mod,$mean,$Solved,$solved,$DegOfDiff,$STD,
+ ##########################################################
-                     $SKEW) = &Apache::loncoursedata::get_problem_statistics
+ ##
-                         (undef,$resource->{'symb'},$part,
+ ## HTML output routines
-                          $ENV{'request.course.id'});
+ ##
-                 my $wrongpercent = 0;
+ ##########################################################
-                 if (defined($num) && $num > 0) {
+ ##########################################################
-                     $wrongpercent=int(10*100*($num-$Solved+$solved)/$num)/10;
+ sub output_html_by_sequence {
-                 }
+     my ($r) = @_;
-                 $r->print('<tr>'.&statistics_html_table_data
+     my $c = $r->connection();
-                           ($resource,$part,$num,$tries,$mod,$mean,$Solved,
+     $r->print('<br />'.&html_preamble());
-                            $solved,$wrongpercent,$DegOfDiff,$STD,$SKEW).
+     #
-                           "</tr>\n");
+     foreach my $seq (@sequences) {
-             }
+         last if ($c->aborted);
+         $r->print("<h3>".$seq->compTitle."</h3>".
+                     &Apache::loncommon::start_data_table().
+                     &Apache::loncommon::start_data_table_header_row().
+                     &statistics_table_header('no container').
+                     &Apache::loncommon::end_data_table_header_row()."\n");
+         my @Data = &compute_statistics_on_sequence($seq);
+         foreach my $data (@Data) {
+             $r->print(&Apache::loncommon::start_data_table_row().
+                     &statistics_html_table_data($data,'no container').
+                     &Apache::loncommon::end_data_table_row()."\n");
          }
-         $r->print("</table>\n");
+         $r->print(&Apache::loncommon::end_data_table()."\n");
-         $r->print("</td></tr></table>\n");
          $r->rflush();
      }
+     return;
+ }
+ sub output_html_stats {
+     my ($r)=@_;
+     &compute_all_statistics($r);
+     $r->print(&html_preamble());
+     &sort_data($env{'form.sortby'});
      #
+     my $count=0;
+     foreach my $data (@StatsArray) {
+         if ($count++ % 50 == 0) {
+             $r->print(&Apache::loncommon::end_data_table());
+             $r->print(&Apache::loncommon::start_data_table().
+                     &Apache::loncommon::start_data_table_row().
+                     &statistics_table_header().
+                     &Apache::loncommon::end_data_table_row());
+         }
+         $r->print(&Apache::loncommon::start_data_table_row().
+                 &statistics_html_table_data($data).
+                 &Apache::loncommon::end_data_table_row());
+     }
+     $r->print(&Apache::loncommon::end_data_table_row());
      return;
  }
+ sub html_preamble {
+     my $Str='';
+     $Str .= "<h2>".
+         $env{'course.'.$env{'request.course.id'}.'.description'}.
+         "</h2>\n";
+     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+     if (defined($starttime) || defined($endtime)) {
+         # Inform the user what the time limits on the data are.
+         $Str .= '<h3>'.&mt('Statistics on submissions from [_1] to [_2]',
+                            &Apache::lonlocal::locallocaltime($starttime),
+                            &Apache::lonlocal::locallocaltime($endtime)
+                            ).'</h3>';
+     }
+     $Str .= "<p>".&mt('Compiled on [_1]',
+                        &Apache::lonlocal::locallocaltime(time))."</p>";
+     return $Str;
+ }
  ###############################################
  ###############################################
+ ##
+ ## Misc HTML output routines
+ ##
  ###############################################
  ###############################################
- sub output_html_ungrouped {
+ sub statistics_html_table_data {
-     my ($r) = @_;
+     my ($data,$options) = @_;
-     #
+     my $row = '';
-     my $sortby = $ENV{'form.sortby'};
+     foreach my $field (@Fields) {
-     if (! defined($sortby) || $sortby eq '') {
+         next if ($options =~ /no $field->{'name'}/);
-         $sortby = 'sequence';
+         next if ($field->{'selected'} ne 'yes');
-     }
+         $row .= '<td style="background-color:'.$field->{'color'}.'"';
-     #
+         if (exists($field->{'align'})) {
-     my $show_container = 0;
+             $row .= ' align="'.$field->{'align'}.'"';
-     #$r->print(&ProblemStatisticsLegend());
+             }
-     my @Header = ("Title","Part","#Stdnts","Tries","Mod",
+         $row .= '>';
-                   "Mean","#YES","#yes","%Wrng","DoDiff",
+         if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
-                   "S.D.","Skew.");#,"D.F.1st","D.F.2nd");
+             $row .= '<a href="'.$data->{$field->{'name'}.'.link'}.'">';
-     # #FFFFE6 #EEFFCC #DDFFFF FFDDDD #DDFFDD #FFDDFF
+         }
-     my @Sequences = &Apache::lonstatistics::Sequences_with_Assess();
+         if (exists($field->{'format'}) && $data->{$field->{'name'}} !~ /[A-Z]/i) {
-     if (@Sequences > 1) {
+             $row .= sprintf($field->{'format'},$data->{$field->{'name'}});
-         unshift(@Header,"Container");
+         } else {
-         $show_container = 1;
+             $row .= $data->{$field->{'name'}};
+         }
+         if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
+             $row.= '</a>';
+         }
+         $row .= '</td>';
+     }
+     return $row;
+ }
+ sub statistics_table_header {
+     my ($options) = @_;
+     my $header_row;
+     foreach my $field (@Fields) {
+         next if ($options =~ /no $field->{'name'}/);
+         next if ($field->{'selected'} ne 'yes');
+         $header_row .= '<th>';
+         my $header_row_text = &mt($field->{'title'});
+         if (exists($field->{'sortable'}) && $field->{'sortable'} eq 'yes') {
+             $header_row .=
+                 '<a href="javascript:'.
+                 'document.Statistics.sortby.value='."'".$field->{'name'}."'".
+                 ';document.Statistics.submit();">'.
+                 $header_row_text.
+                 '</a>';
+         } else {
+             $header_row .= $header_row_text;
+         }
+         if ($options !~ /no plots/        &&
+             exists($field->{'graphable'}) &&
+             $field->{'graphable'} eq 'yes') {
+             $header_row.=' (';
+             $header_row .= '<a href="javascript:'.
+                 "document.Statistics.plot.value='$field->{'name'}'".
+                     ';document.Statistics.submit();">';
+             $header_row .= &mt('plot').'</a>)';
+         }
+         $header_row .= '</th>';
+     }
+     return $header_row;
+ }
+ sub sequence_html_header {
+     my $Str .= &Apache::loncommon::start_data_table_header_row();
+     foreach my $field (@SeqFields) {
+ #        next if ($field->{'selected'} ne 'yes');
+         $Str .= '<th bgcolor="'.$field->{'color'}.'"';
+         $Str .= '>'.&mt($field->{'title'}).'</th>';
+     }
+     $Str .= &Apache::loncommon::end_data_table_header_row();
+     return $Str;
+ }
+ sub sequence_html_output {
+     my ($seq) = @_;
+     my $data = $SeqStat{$seq->symb};
+     my $row = &Apache::loncommon::start_data_table_row();
+     foreach my $field (@SeqFields) {
+         next if ($field->{'selected'} ne 'yes');
+         $row .= '<td bgcolor="'.$field->{'color'}.'"';
+         if (exists($field->{'align'})) {
+             $row .= ' align="'.$field->{'align'}.'"';
+         }
+         $row .= '>';
+         if (exists($field->{'format'})) {
+             $row .= sprintf($field->{'format'},$data->{$field->{'name'}});
+         } else {
+             $row .= $data->{$field->{'name'}};
+         }
+         $row .= '</td>';
+     }
+     $row .= &Apache::loncommon::end_data_table_row()."\n";
+     return $row;
+ }
+ ####################################################
+ ####################################################
+ ##
+ ##    Plotting Routines
+ ##
+ ####################################################
+ ####################################################
+ sub make_plot {
+     my ($r,$plot) = @_;
+     &compute_all_statistics($r);
+     &sort_data($env{'form.sortby'});
+     if ($plot eq 'degrees') {
+         &degrees_plot($r);
+     } elsif ($plot eq 'tries statistics') {
+         &tries_data_plot($r);
+     } else {
+         &make_single_stat_plot($r,$plot);
      }
+     return;
+ }
+ sub make_single_stat_plot {
+     my ($r,$datafield) = @_;
      #
-     $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+     my $title; my $yaxis;
-     $r->print('<table border="0" cellpadding="3">'."\n");
+     foreach my $field (@Fields) {
-     my $Str = '';
+         next if ($field->{'name'} ne $datafield);
-     foreach (@Header) {
+         $title = &mt($field->{'long_title'});
-         $Str .= '<th>'.
+         $yaxis = &mt($field->{'title'});
-      '<a href="javascript:document.Statistics.sortby.value='."'$_'".
+         last;
-          ';document.Statistics.submit();">'.
+     }
-          $_.'</a></th>';
+     if ($title eq '' || $yaxis eq '') {
+         # datafield is something we do not know enough about to plot
+         $r->print('<p class="LC_warning">'.
+                   &mt('Unable to plot the requested statistic.').
+                   '</p>');
+         return;
      }
-     $r->print('<tr bgcolor="#FFFFE6">'.$Str."</tr>\n");
-     $r->rflush();
      #
-     foreach my $sequence (@Sequences) {
+     # Build up the data sets to plot
-         next if ($sequence->{'num_assess'}<1);
+     my @Labels;
-         foreach my $resource (@{$sequence->{'contents'}}) {
+     my @Data;
-             next if ($resource->{'type'} ne 'assessment');
+     my $max = 1;
-             foreach my $part (@{$resource->{'parts'}}) {
+     foreach my $data (@StatsArray) {
-                 my ($num,$tries,$mod,$mean,$Solved,$solved,$DegOfDiff,$STD,
+         push(@Labels,$data->{'problem_num'});
-                     $SKEW) = &Apache::loncoursedata::get_problem_statistics
+         push(@Data,$data->{$datafield});
-                         (undef,$resource->{'symb'},$part,
+         if ($data->{$datafield}>$max) {
-                          $ENV{'request.course.id'});
+             $max = $data->{$datafield};
-                 if ($part == 0) {
-                     $part = '&nbsp;';
-                 }
-                 my $wrongpercent = 0;
-                 if (defined($num) && $num > 0) {
-                     $wrongpercent=int(10*100*($num-$Solved+$solved)/$num)/10;
-                 }
-                 if ($show_container) {
-                     $r->print('<tr>'.
-                               '<td bgcolor="#FFFFE6">'.$sequence->{'title'}.
-                               '</td>'.
-                               &statistics_html_table_data
-                               ($resource,$part,$num,$tries,$mod,$mean,$Solved,
-                                $solved,$wrongpercent,$DegOfDiff,$STD,$SKEW).
-                               "</tr>\n");
-                 } else {
-                     $r->print('<tr>'.&statistics_html_table_data
-                               ($resource,$part,$num,$tries,$mod,$mean,$Solved,
-                                $solved,$wrongpercent,$DegOfDiff,$STD,$SKEW).
-                               "</tr>\n");
-                 }
-             }
          }
      }
-     $r->print("</table>\n");
+     foreach (1,2,3,4,5,10,15,20,25,40,50,75,100,150,200,250,300,500,600,750,
-     $r->print("</td></tr></table>\n");
+,1500,2000,2500,3000,3500,4000,5000,7500,10000,15000,20000) {
-     $r->rflush();
+         if ($max <= $_) {
+             $max = $_;
+             last;
+         }
+     }
+     if ($max > 20000) {
+         $max = 10000*(int($max/10000)+1);
+     }
      #
+     $r->print("<p>".&Apache::loncommon::DrawBarGraph($title,
+                                                      &mt('Problem Number'),
+                                                      $yaxis,
+                                                      $max,
+                                                      undef, # colors
+                                                      \@Labels,
+                                                      \@Data)."</p>\n");
      return;
  }
- ###############################################
+ sub degrees_plot {
- ###############################################
+     my ($r)=@_;
+     my $count = scalar(@StatsArray);
+     my $width = 50 + 10*$count;
+     $width = 300 if ($width < 300);
+     my $height = 300;
+     my $plot = '';
+     my $ymax = 0;
+     my $ymin = 0;
+     my @Disc; my @Diff; my @Labels;
+     foreach my $data (@StatsArray) {
+         push(@Labels,$data->{'problem_num'});
+         my $disc = $data->{'deg_of_disc'};
+         my $diff = $data->{'deg_of_diff'};
+         push(@Disc,$disc);
+         push(@Diff,$diff);
+         #
+         $ymin = $disc if ($ymin > $disc);
+         $ymin = $diff if ($ymin > $diff);
+         $ymax = $disc if ($ymax < $disc);
+         $ymax = $diff if ($ymax < $diff);
+     }
+     #
+     # Make sure we show relevant information.
+     if ($ymin < 0) {
+         if (abs($ymin) < 0.05) {
+             $ymin = 0;
+         } else {
+             $ymin = -1;
+         }
+     }
+     if ($ymax > 0) {
+         if (abs($ymax) < 0.05) {
+             $ymax = 0;
+         } else {
+             $ymax = 1;
+         }
+     }
+     #
+     my $xmax = $Labels[-1];
+     if ($xmax > 50) {
+         if ($xmax % 10 != 0) {
+             $xmax = 10 * (int($xmax/10)+1);
+         }
+     } else {
+         if ($xmax % 5 != 0) {
+             $xmax = 5 * (int($xmax/5)+1);
+         }
+     }
+     #
+     my $discdata .= '<data>'.join(',',@Labels).'</data>'.$/.
+                     '<data>'.join(',',@Disc).'</data>'.$/;
+     #
+     my $diffdata .= '<data>'.join(',',@Labels).'</data>'.$/.
+                     '<data>'.join(',',@Diff).'</data>'.$/;
+     #
+     my $title = &mt('Degree of Discrimination[_1]and Degree of Difficulty','\n');
+     if ($xmax > 50) {
+         $title = &mt('Degree of Discrimination and Degree of Difficulty');
+     }
+     my %lt = &Apache::lonlocal::texthash(
+         'alttag' => 'Degree of Discrimination and Degree of Difficulty Plot',
+         'xlabel' => 'Problem Number',
+     );
+     #
+     $plot=<<"END";
+ <gnuplot
+     texfont="10"
+     fgcolor="x000000"
+     plottype="Cartesian"
+     font="large"
+     grid="on"
+     align="center"
+     border="on"
+     transparent="on"
+     alttag="$lt{'alttag'}"
+     samples="100"
+     bgcolor="xffffff"
+     height="$height"
+     width="$width">
+     <key
+         pos="top right"
+         title=""
+         box="off" />
+     <title>$title</title>
+     <axis xmin="0" ymin="$ymin" xmax="$xmax" ymax="$ymax" color="x000000" />
+     <xlabel>$lt{'xlabel'}</xlabel>
+     <curve
+         linestyle="linespoints"
+         name="DoDisc"
+         pointtype="0"
+         color="x000000">
+         $discdata
+     </curve>
+     <curve
+         linestyle="linespoints"
+         name="DoDiff"
+         pointtype="0"
+         color="xFF0000">
+         $diffdata
+     </curve>
+ </gnuplot>
+ END
+     my $plotresult =
+         '<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
+     $r->print($plotresult);
+     return;
+ }
- ###############################################
+ sub tries_data_plot {
- ###############################################
+     my ($r)=@_;
- sub statistics_html_table_data {
+     my $count = scalar(@StatsArray);
-     my ($resource,$part,$num,$tries,$mod,$mean,$Solved,$solved,$wrongpercent,
+     my $width = 50 + 10*$count;
-         $DegOfDiff,$STD,$SKEW) = @_;
+     $width = 300 if ($width < 300);
-     my $row = '';
+     my $height = 300;
-     $row .= '<td bgcolor="#FFFFE6">'.
+     my $plot = '';
-         '<a href="'.$resource->{'src'}.'" target="_blank" >'.
+     my @STD;  my @Mean; my @Max; my @Min;
-             $resource->{'title'}.'</a>'.
+     my @Labels;
-                 '</td>';
+     my $ymax = 5;
-     $row .= '<td bgcolor="#FFFFE6">'.$part.'</td>' if (defined($part));
+     foreach my $data (@StatsArray) {
-     foreach ($num,$tries) {
+         my $max = $data->{'mean_tries'} + $data->{'std_tries'};
-         $row .= '<td bgcolor="#EEFFCC" align="right">'.$_.'</td>';
+         $ymax = $max if ($ymax < $max);
-     }
+         $ymax = $max if ($ymax < $max);
-     foreach ($mod,$mean) {
+         push(@Labels,$data->{'problem_num'});
-         $row .= '<td bgcolor="#DDFFFF" align="right">'.
+         push(@STD,$data->{'std_tries'});
-                   sprintf("%5.2f",$_).'</td>';
+         push(@Mean,$data->{'mean_tries'});
-     }
-     foreach ($Solved,$solved) {
-         $row .= '<td bgcolor="#DDFFFF" align="right">'.$_.'</td>';
-     }
-     foreach ($wrongpercent) {
-         $row .= '<td bgcolor="#DDFFFF" align="right">'.
-                   sprintf("%5.1f",$_).'</td>';
-     }
-     foreach ($DegOfDiff,$STD,$SKEW) {
-         $row .= '<td bgcolor="#FFDDDD" align="right">'.
-                   sprintf("%5.2f",$_).'</td>';
      }
-     return $row;
+     #
+     # Make sure we show relevant information.
+     my $xmax = $Labels[-1];
+     if ($xmax > 50) {
+         if ($xmax % 10 != 0) {
+             $xmax = 10 * (int($xmax/10)+1);
+         }
+     } else {
+         if ($xmax % 5 != 0) {
+             $xmax = 5 * (int($xmax/5)+1);
+         }
+     }
+     $ymax = int($ymax)+1+2;
+     #
+     my $std_data .= '<data>'.join(',',@Labels).'</data>'.$/.
+                     '<data>'.join(',',@Mean).'</data>'.$/;
+     #
+     my $std_error_data .= '<data>'.join(',',@Labels).'</data>'.$/.
+                           '<data>'.join(',',@Mean).'</data>'.$/.
+                           '<data>'.join(',',@STD).'</data>'.$/;
+     #
+     my $title = &mt('Mean and S.D. of Tries');
+     if ($xmax > 30) {
+         $title = &mt('Mean and Standard Deviation of Tries');
+     }
+     #
+     my %lt = &Apache::lonlocal::texthash(
+         'alttag' => 'Mean and S.D of Tries Plot',
+         'xlabel' => 'Problem Number',
+         'ylabel' => 'Number of Tries',
+     );
+     $plot=<<"END";
+ <gnuplot
+     texfont="10"
+     fgcolor="x000000"
+     plottype="Cartesian"
+     font="large"
+     grid="on"
+     align="center"
+     border="on"
+     transparent="on"
+     alttag="$lt{'alttag'}"
+     samples="100"
+     bgcolor="xffffff"
+     height="$height"
+     width="$width">
+     <title>$title</title>
+     <axis xmin="0" ymin="0" xmax="$xmax" ymax="$ymax" color="x000000" />
+     <xlabel>$lt{'xlabel'}</xlabel>
+     <ylabel>$lt{'ylabel'}</ylabel>
+     <curve
+         linestyle="yerrorbars"
+         name="S.D. Tries"
+         pointtype="1"
+         color="x666666">
+         $std_error_data
+     </curve>
+     <curve
+         linestyle="points"
+         name="Mean Tries"
+         pointtype="1"
+         color="xCC4444">
+         $std_data
+     </curve>
+ </gnuplot>
+ END
+     my $plotresult =
+         '<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
+     $r->print($plotresult);
+     return;
  }
+ sub plot_dropdown {
+     my $current = '';
+     my $title;
+     #
+     if (defined($env{'form.plot'})) {
+         $current = $env{'form.plot'};
+     }
+     #
+     my @Additional_Plots = (
+                             { graphable=>'yes',
+                               name => 'degrees',
+                               title => 'Difficulty Indexes' },
+                             { graphable=>'yes',
+                               name => 'tries statistics',
+                               title => 'Tries Statistics' });
+     #
+     my $Str= "\n".'<select name="plot" size="1">';
+     $Str .= '<option name="none"></option>'."\n";
+     $Str .= '<option name="none2">'.&mt('none').'</option>'."\n";
+     foreach my $field (@Additional_Plots,@Fields) {
+         if (! exists($field->{'graphable'}) ||
+             $field->{'graphable'} ne 'yes') {
+             next;
+         }
+         $Str .= '<option value="'.$field->{'name'}.'"';
+         if ($field->{'name'} eq $current) {
+             $Str .= ' selected="selected"';
+         }
+         $title = &mt($field->{'long_title'});
+         $title = &mt($field->{'title'}) if (!$title);
+         $Str.= '>'.$title.'</option>'."\n";
+     }
+     $Str .= '</select>'."\n";
+     return $Str;
+ }
  ###############################################
  ###############################################
+ ##
- sub BuildGraphicChart {
+ ## Excel output routines
-     my ($graph,$cacheDB,$courseDescription,$students,$courseID,$r,$c)=@_;
+ ##
-     my %cache;
+ ###############################################
-     my $max;
+ ###############################################
-     my $title = '';
+ sub Excel_output {
-     if($graph eq 'DoDiffGraph') {
+     my ($r) = @_;
- 	$title = 'Degree-of-Difficulty';
+     $r->print('<h2>'.&mt('Preparing Excel Spreadsheet').'</h2>');
-     } else {
+     ##
- 	$title = 'Wrong-Percentage';
+     ## Compute the statistics
+     &compute_all_statistics($r);
+     my $c = $r->connection;
+     return if ($c->aborted());
+     #
+     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+     ##
+     ## Create the excel workbook
+     my ($excel_workbook,$filename,$format) =
+         &Apache::loncommon::create_workbook($r);
+     return if (! defined($excel_workbook));
+     #
+     # Add a worksheet
+     my $sheetname = $env{'course.'.$env{'request.course.id'}.'.description'};
+     if (length($sheetname) > 31) {
+         $sheetname = substr($sheetname,0,31);
+     }
+     my $excel_sheet = $excel_workbook->addworksheet(
+         &Apache::loncommon::clean_excel_name($sheetname));
+     ##
+     ## Begin creating excel sheet
+     ##
+     my ($rows_output,$cols_output) = (0,0);
+     #
+     # Put the course description in the header
+     $excel_sheet->write($rows_output,$cols_output++,
+                    $env{'course.'.$env{'request.course.id'}.'.description'},
+                         $format->{'h1'});
+     $cols_output += 3;
+     #
+     # Put a description of the sections listed
+     my $sectionstring = '';
+     $excel_sheet->write($rows_output,$cols_output++,
+                         &Apache::lonstatistics::section_and_enrollment_description('plaintext'),
+                         $format->{'h3'});
+     $cols_output += scalar(&Apache::lonstatistics::get_selected_sections());
+     $cols_output += scalar(&Apache::lonstatistics::get_selected_groups());
+     #
+     # Time restrictions
+     my $time_string;
+     if (defined($starttime)) {
+         if (defined($endtime)) {
+             $time_string .=  &mt('Data collected from [_1] to [_2]',
+                                  &Apache::lonlocal::locallocaltime($starttime),
+                                  &Apache::lonlocal::locallocaltime($endtime));
+         } else {
+             $time_string .=  &mt('Data collected from [_1]',
+                                  &Apache::lonlocal::locallocaltime($starttime));
+         }
+     } elsif (defined($endtime)) {
+         $time_string .=  &mt('Data collected before [_1]',
+                              &Apache::lonlocal::locallocaltime($endtime));
+     }
+     if (defined($time_string)) {
+         $excel_sheet->write($rows_output,$cols_output++,$time_string);
+         $cols_output+= 5;
      }
-     my $currentSequence = -1;
+     #
-     my $sortProblems = 'Sort Within Sequence';
+     # Put the date in there too
-     my ($result, $orderedProblems) =
+     $excel_sheet->write($rows_output,$cols_output++,
-         &InitializeProblemStatistics($cacheDB, $students, $courseID, $c, $r);
+                         &mt('Compiled on [_1]',&Apache::lonlocal::locallocaltime(time)));
-     if($result ne 'OK') {
+     #
-         return;
+     $rows_output++;
+     $cols_output=0;
+     ##
+     ## Sequence Statistics
+     ##
+     &write_headers($excel_sheet,$format,\$rows_output,\$cols_output,
+                    \@SeqFields);
+     foreach my $seq (@sequences) {
+         my $data = $SeqStat{$seq->symb};
+         $cols_output=0;
+         foreach my $field (@SeqFields) {
+             next if ($field->{'selected'} ne 'yes');
+             my $fieldformat = undef;
+             if (exists($field->{'excel_format'})) {
+                 $fieldformat = $format->{$field->{'excel_format'}};
+             }
+             $excel_sheet->write($rows_output,$cols_output++,
+                                 $data->{$field->{'name'}},$fieldformat);
+         }
+         $rows_output++;
+         $cols_output=0;
      }
-     my @values = ();
+     ##
-     unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+     ## Resource Statistics
-         return 'Unable to tie database.7';
+     ##
-     }
+     $rows_output++;
-     foreach(@$orderedProblems) {
+     $cols_output=0;
-         my ($sequence,$problem,$part)=split(':', $_);
+     &write_headers($excel_sheet,$format,\$rows_output,\$cols_output,
-         if($cache{'StatisticsMaps'} ne 'All Maps'  &&
+                    \@Fields);
-            $cache{'StatisticsMaps'} ne $cache{$sequence.':title'}) {
+     #
-              next;
+     foreach my $data (@StatsArray) {
-         }
+         $cols_output=0;
-         if( $currentSequence == -1 ||
+         foreach my $field (@Fields) {
-             ($sortProblems eq 'Sort Within Sequence' &&
+             next if ($field->{'selected'} ne 'yes');
-             $currentSequence != $sequence)) {
+             next if ($field->{'name'} eq 'problem_num');
- 	    if($currentSequence != -1) {
+             my $fieldformat = undef;
- 		&DrawGraph(\@values,$courseDescription,$title,$max,$r);
+             if (exists($field->{'excel_format'})) {
- 	    }
+                 $fieldformat = $format->{$field->{'excel_format'}};
-             if($sortProblems eq 'Sort Within Sequence') {
-                 $r->print('<br><b>'.$cache{$sequence.':title'}.'</b>'."\n");
              }
-             $currentSequence = $sequence;
+             $excel_sheet->write($rows_output,$cols_output++,
-             @values = ();
+                                 $data->{$field->{'name'}},$fieldformat);
- 	    $max=0;
+         }
-         }
+         $rows_output++;
-         my $data = 0;
+         $cols_output=0;
-         if($graph eq 'DoDiffGraph') {
+     }
-             $data = sprintf("%.2f", $cache{$_.':degreeOfDifficulty'}),
+     #
-         } else {
+     $excel_workbook->close();
-             $data = sprintf("%.1f", $cache{$_.':percentWrong'}),
+     #
-         }
+     # Tell the user where to get their excel file
-         if($max < $data) {
+     $r->print('<br />'.
-             $max = $data;
+               '<a href="'.$filename.'">'.
-         }
+               &mt('Your Excel Spreadsheet').'</a>'."\n");
-         push(@values, $data);
+     $r->rflush();
-     }
-     untie(%cache);
-     &DrawGraph(\@values,$courseDescription,$title,$max,$r);
      return;
  }
- sub DrawGraph {
+ ##
-     my ($values,$courseDescription,$title,$Max,$r)=@_;
+ ## &write_headers
-     my $sendValues = join(',', @$values);
+ ##
-     my $sendCount = scalar(@$values);
+ sub write_headers {
-     $r->print("<br>The Maximum Value is: $Max");
+     my ($excel_sheet,$format,$rows_output,$cols_output,$Fields) = @_;
-     if ( $Max > 1 ) {
+     ##
- 	if ($Max % 10) {
+     ## First the long titles
-             if ( int($Max) < $Max ) {
+     foreach my $field (@{$Fields}) {
- 	    	$Max++;
+         next if ($field->{'name'} eq 'problem_num');
- 		$Max = int($Max);
+         next if ($field->{'selected'} ne 'yes');
- 	    }
+         if (exists($field->{'long_title'})) {
- 	}
+             $excel_sheet->write($$rows_output,${$cols_output},
-     #(10 - $Max % 10);
+                                 $field->{'long_title'},
-     } else { $Max = 1; }
+                                 $format->{'bold'});
-     my @GData = ('','Problem_number',$title,$Max,$sendCount,$sendValues);
+         } else {
- #    $r->print('</form>'."\n");
+             $excel_sheet->write($$rows_output,${$cols_output},'');
-     $r->print('<br>'."\n");
+         }
-     $r->print('<IMG src="/cgi-bin/graph.png?'.
+         ${$cols_output}+= 1;
-               (join('&', @GData)).'" border="1" />');
- #    $r->print('<form>'."\n");
-     $r->print('<br>'."\n");
- }
- #---- Problem Statistics Web Page ---------------------------------------
- sub CreateProblemStatisticsTableHeading {
-     my ($headings,$r)=@_;
-     my $Str='';
-     $Str .= '<tr>'."\n";
-     $Str .= '<th bgcolor="#ffffe6">P#</th>'."\n";
-     foreach(@$headings) {
- 	$Str .= '<th bgcolor="#ffffe6">';
-         $Str .= '<a href="/adm/statistics?reportSelected=';
-         $Str .= &Apache::lonnet::escape('Problem Statistics');
-         $Str .= '&ProblemStatisticsSort=';
-         $Str .= &Apache::lonnet::escape($_).'">'.$_.'</a>&nbsp</th>'."\n";
      }
-     $Str .= "\n".'</tr>'."\n";
+     ${$cols_output} =0;
-     return $Str;
+     ${$rows_output}+=1;
+     ##
+     ## Then the short titles
+     foreach my $field (@{$Fields}) {
+         next if ($field->{'selected'} ne 'yes');
+         next if ($field->{'name'} eq 'problem_num');
+         # Use english for excel as I am not sure how well excel handles
+         # other character sets....
+         $excel_sheet->write($$rows_output,$$cols_output,
+                             $field->{'title'},
+                             $format->{'bold'});
+         $$cols_output+=1;
+     }
+     ${$cols_output} =0;
+     ${$rows_output}+=1;
+     return;
  }
- sub BuildStatisticsTable {
+ ##################################################
-     my ($cache,$displayFormat,$sortProblems,$orderedProblems,$headings,
+ ##################################################
-         $r,$color)=@_;
+ ##
-     my $count = 1;
+ ## Statistics Gathering and Manipulation Routines
-     my $currentSequence = -1;
+ ##
-     foreach(@$orderedProblems) {
+ ##################################################
-         my ($sequence,$problem,$part)=split(':', $_);
+ ##################################################
-         if($cache->{'StatisticsMaps'} ne 'All Maps'  &&
+ sub compute_statistics_on_sequence {
-            $cache->{'StatisticsMaps'} ne $cache->{$sequence.':title'}) {
+     my ($seq) = @_;
-             next;
+     my @Data;
+     foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)) {
+         foreach my $part (@{$res->parts}) {
+             next if (($res->is_survey($part)) || ($res->is_anonsurvey($part))) ;
+             #
+             # This is where all the work happens
+             my $data = &get_statistics($seq,$res,$part,scalar(@StatsArray)+1);
+             push (@Data,$data);
+             push (@StatsArray,$data);
+         }
+     }
+     return @Data;
+ }
+ sub compute_all_statistics {
+     my ($r) = @_;
+     if (@StatsArray > 0) {
+         # Assume we have already computed the statistics
+         return;
+     }
+     my $c = $r->connection;
+     foreach my $seq (@sequences) {
+         last if ($c->aborted);
+         &compute_sequence_statistics($seq);
+         &compute_statistics_on_sequence($seq);
+     }
+ }
+ sub sort_data {
+     my ($sortkey) = @_;
+     return if (! @StatsArray);
+     #
+     # Sort the data
+     my $sortby = undef;
+     foreach my $field (@Fields) {
+         if ($sortkey eq $field->{'name'}) {
+             $sortby = $field->{'name'};
          }
-         if($currentSequence == -1 ||
+     }
-            ($sortProblems eq 'Sort Within Sequence' &&
+     if (! defined($sortby) || $sortby eq '' || $sortby eq 'problem_num') {
-             $currentSequence != $sequence)) {
+         $sortby = 'container';
-             if($displayFormat ne 'Display CSV Format') {
+     }
-                 if($currentSequence ne -1) {
+     if ($sortby ne 'container') {
-                     $r->print('</table>');
+         # $sortby is already defined, so we can charge ahead
-                     $r->print('</td></tr></table><br>');
+         if ($sortby =~ /^(title|part)$/i) {
+             # Alpha comparison
+             @StatsArray = sort {
+                 lc($a->{$sortby}) cmp lc($b->{$sortby}) ||
+                 lc($a->{'title'}) cmp lc($b->{'title'}) ||
+                 lc($a->{'part'}) cmp lc($b->{'part'});
+             } @StatsArray;
+         } else {
+             # Numerical comparison
+             @StatsArray = sort {
+                 my $retvalue = 0;
+                 if ($b->{$sortby} eq 'nan') {
+                     if ($a->{$sortby} ne 'nan') {
+                         $retvalue = -1;
+                     } else {
+                         $retvalue = 0;
+                     }
                  }
-                 if($sortProblems eq 'Sort Within Sequence') {
+                 if ($a->{$sortby} eq 'nan') {
-                     $r->print('<b>'.$cache->{$sequence.':title'}.'</b>');
+                     if ($b->{$sortby} ne 'nan') {
+                         $retvalue = 1;
+                     }
                  }
-                 $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+                 if ($retvalue eq '0') {
-                 $r->print('<table border="0" cellpadding="3">'."\n");
+                     $retvalue = $b->{$sortby} <=> $a->{$sortby}     ||
-                 $r->print(&CreateProblemStatisticsTableHeading($headings, $r));
+                             lc($a->{'title'}) <=> lc($b->{'title'}) ||
-             } else {
+                             lc($a->{'part'})  <=> lc($b->{'part'});
-                 if($sortProblems eq 'Sort Within Sequence') {
-                     $r->print('"'.$cache->{$sequence.':title'}.'"');
                  }
-                 $r->print('<br>');
+                 $retvalue;
-             }
+             } @StatsArray;
-             $currentSequence = $sequence;
          }
-         my $ref = '<a href="'.$cache->{$problem.':source'}.
+     }
-                   '" target="_blank">'.$cache->{$problem.':title'}.'</a>';
+     #
-         my $title = $cache->{$problem.':title'};
+     # Renumber the data set
-         if($part != 0) {
+     my $count;
-             $title .= ' Part '.$part;
+     foreach my $data (@StatsArray) {
-         }
+         $data->{'problem_num'} = ++$count;
-         my $source = $cache->{$problem.':source'};
-         my $tableData = join('&', $ref, $title, $source,
-                        $cache->{$_.':studentCount'},
-                        $cache->{$_.':totalTries'},
-                        $cache->{$_.':maxTries'},
-                        $cache->{$_.':mean'},
-                        $cache->{$_.':correct'},
-                        $cache->{$_.':correctByOverride'},
-                        $cache->{$_.':percentWrong'},
-                        $cache->{$_.':degreeOfDifficulty'},
-                        $cache->{$_.':standardDeviation'},
-                        $cache->{$_.':skewness'},
-                        $cache->{$_.':discriminationFactor1'},
-                        $cache->{$_.':discriminationFactor2'});
-         &TableRow($displayFormat,$tableData,$count,$r,$color);
-         $count++;
-     }
-     if($displayFormat ne 'Display CSV Format') {
-         $r->print('</table>'."\n");
-         $r->print('</td></tr></table>');
-     } else {
-         $r->print('<br>');
      }
      return;
  }
- sub TableRow {
+ ########################################################
-     my ($displayFormat,$Str,$RealIdx,$r,$color)=@_;
+ ########################################################
-     my($ref,$title,$source,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
-        $Wrng,$DoD,$SD,$Sk,$_D1,$_D2)=split(/\&/,$Str);
+ =pod
-     my $Ptr;
-     if($displayFormat eq 'Display CSV Format') {
+ =item &get_statistics()
-         $Ptr='"'.$RealIdx.'",'."\n".
-              '"'.$title.'",'."\n".
+ Wrapper routine from the call to loncoursedata::get_problem_statistics.
-              '"'.$source.'",'."\n".
+ Calls lonstathelpers::get_time_limits() to limit the data set by time
-              '"'.$StdNo.'",'."\n".
+ and &compute_discrimination_factor
-              '"'.$TotalTries.'",'."\n".
-              '"'.$MxTries.'",'."\n".
+ Inputs: $sequence, $resource, $part, $problem_num
-              '"'.$Avg.'",'."\n".
-              '"'.$YES.'",'."\n".
+ Returns: Hash reference with statistics data from
-              '"'.$Override.'",'."\n".
+ loncoursedata::get_problem_statistics.
-              '"'.$Wrng.'",'."\n".
-              '"'.$DoD.'",'."\n".
+ =cut
-              '"'.$SD.'",'."\n".
-              '"'.$Sk.'",'."\n".
+ ########################################################
-              '"'.$_D1.'",'."\n".
+ ########################################################
-              '"'.$_D2.'"'."\n".
+ sub get_statistics {
-              "<br>\n";
+     my ($sequence,$resource,$part,$problem_num) = @_;
-         $r->print("\n".$Ptr);
+     #
-     } else {
+     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
-         $Ptr='<tr>'."\n".
+     my $symb = $resource->symb;
-              '<td bgcolor="#ffffe6">'.$RealIdx.'</td>'."\n".
+     my $courseid = $env{'request.course.id'};
-              '<td bgcolor="#ffffe6">'.$ref.'</td>'."\n".
+     #
-              '<td bgcolor='.$color->{"yellow"}.'> '.$StdNo.'</td>'."\n".
+     my $data = &Apache::loncoursedata::get_problem_statistics
-              '<td bgcolor='.$color->{"yellow"}.'>'.$TotalTries.'</td>'."\n".
+                         ([&Apache::lonstatistics::get_selected_sections()],
-              '<td bgcolor='.$color->{"yellow"}.'>'.$MxTries.'</td>'."\n".
+                          [&Apache::lonstatistics::get_selected_groups()],
-              '<td bgcolor='.$color->{"gb"}.'>'.$Avg.'</td>'."\n".
+                          $Apache::lonstatistics::enrollment_status,
-              '<td bgcolor='.$color->{"gb"}.'> '.$YES.'</td>'."\n".
+                          $symb,$part,$courseid,$starttime,$endtime);
-              '<td bgcolor='.$color->{"gb"}.'> '.$Override.'</td>'."\n".
+     $data->{'symb'}        = $symb;
-              '<td bgcolor='.$color->{"red"}.'> '.$Wrng.'</td>'."\n".
+     $data->{'part'}        = $part;
-              '<td bgcolor='.$color->{"red"}.'> '.$DoD.'</td>'."\n".
+     $data->{'problem_num'} = $problem_num;
-              '<td bgcolor='.$color->{"green"}.'> '.$SD.'</td>'."\n".
+     $data->{'container'}   = $sequence->compTitle;
-              '<td bgcolor='.$color->{"green"}.'> '.$Sk.'</td>'."\n".
+     $data->{'title'}       = $resource->compTitle;
-              '<td bgcolor='.$color->{"purple"}.'> '.$_D1.'</td>'."\n".
+     $data->{'title.link'}  = $resource->src.'?symb='.
- 	     '<td bgcolor='.$color->{"purple"}.'> '.$_D2.'</td>'."\n";
+         &escape($resource->symb);
-         $r->print($Ptr.'</tr>'."\n");
+     #
+     if ($SelectedFields{'deg_of_disc'}) {
+         $data->{'deg_of_disc'} =
+             &compute_discrimination_factor($resource,$part,$sequence);
      }
-     return;
+     #
+     # Store in metadata if computations were done for all students
+     if ($data->{'num_students'} > 1) {
+         my @Sections = &Apache::lonstatistics::get_selected_sections();
+         my $sections = '"'.join(' ',@Sections).'"';
+         $sections =~ s/&+/_/g;  # Ensure no special characters
+         $data->{'sections'}=$sections;
+         $data->{'course'} = $env{'request.course.id'};
+         my $urlres=(&Apache::lonnet::decode_symb($resource->symb))[2];
+         my %storestats =
+             &LONCAPA::lonmetadata::dynamic_metadata_storage($data);
+         my ($dom,$user) = ($urlres=~m{^($LONCAPA::domain_re)/($LONCAPA::username_re)});
+         &Apache::lonnet::put('nohist_resevaldata',\%storestats,$dom,$user);
+     }
+     #
+     $data->{'tries_per_correct'} = $data->{'tries'} /
+         ($data->{'num_solved'}+0.1);
+     #
+     # Get the due date for research purposes (commented out most of the time)
+ #    my $duedate = &Apache::lonnet::EXT('resource.'.$part.'.duedate',$symb);;
+ #    my $opendate = &Apache::lonnet::EXT('resource.'.$part.'.opendate',$symb);
+ #    my $maxtries = &Apache::lonnet::EXT('resource.'.$part.'.maxtries',$symb);
+ #    my $hinttries = &Apache::lonnet::EXT('resource.'.$part.'.hinttries',$symb);
+     my $weight = &Apache::lonnet::EXT('resource.'.$part.'.weight',$symb);
+     $data->{'weight'} = $weight;
+ #    $data->{'duedate'} = $duedate;
+ #    $data->{'opendate'} = $opendate;
+ #    $data->{'maxtries'} = $maxtries;
+ #    $data->{'hinttries'} = $hinttries;
+ #    $data->{'resptypes'} = join(',',@{$resource->{'partdata'}->{$part}->{'ResponseTypes'}});
+     return $data;
  }
- # For loading the colored table for display or un-colored for print
+ ###############################################
- sub setbgcolor {
+ ###############################################
-     my $PrintTable=shift;
-     my %color;
+ =pod
-     if ($PrintTable){
- 	$color{"gb"}="#FFFFFF";
+ =item &compute_discrimination_factor()
- 	$color{"red"}="#FFFFFF";
- 	$color{"yellow"}="#FFFFFF";
+ Inputs: $Resource, $Sequence
- 	$color{"green"}="#FFFFFF";
- 	$color{"purple"}="#FFFFFF";
+ Returns: integer between -1 and 1
-     } else {
- 	$color{"gb"}="#DDFFFF";
+ =cut
- 	$color{"red"}="#FFDDDD";
- 	$color{"yellow"}="#EEFFCC";
+ ###############################################
- 	$color{"green"}="#DDFFDD";
+ ###############################################
- 	$color{"purple"}="#FFDDFF";
+ sub compute_discrimination_factor {
-     }
+     my ($resource,$part,$seq) = @_;
-     return \%color;
+     my $symb = $resource->symb;
- }
+     my @Resources;
+     foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)){
- sub ProblemStatisticsButtons {
+         next if ($res->symb eq $symb);
-     my ($displayFormat, $displayLegend, $sortProblems)=@_;
+         push (@Resources,$res->symb);
-     my $Ptr = '<tr><td></td><td align="left">';
-     $Ptr .= '<input type="submit" name="DoDiffGraph" ';
-     $Ptr .= 'value="Plot Degree of Difficulty" />'."\n";
-     $Ptr .= '</td><td align="left">';
-     $Ptr .= '<input type="submit" name="PercentWrongGraph" ';
-     $Ptr .= 'value="Plot Percent Wrong" />'."\n";
-     $Ptr .= '</td></tr><tr><td></td><td>'."\n";
-     $Ptr .= '<input type="submit" name="SortProblems" ';
-     if($sortProblems eq 'Sort All Problems') {
-         $Ptr .= 'value="Sort Within Sequence" />'."\n";
-     } else {
-         $Ptr .= 'value="Sort All Problems" />'."\n";
      }
-     $Ptr .= '</td><td align="left">';
+     #
-     $Ptr .= '<input type="submit" name="DisplayLegend" ';
+     # rank
-     if($displayLegend eq 'Show Legend') {
+     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
-         $Ptr .= 'value="Hide Legend" />'."\n";
+     my $ranking =
+         &Apache::loncoursedata::rank_students_by_scores_on_resources
+         (\@Resources,
+          [&Apache::lonstatistics::get_selected_sections()],
+          [&Apache::lonstatistics::get_selected_groups()],
+          $Apache::lonstatistics::enrollment_status,undef,
+          $starttime,$endtime, $symb);
+     #
+     # compute their percent scores on the problems in the sequence,
+     my $number_to_grab = int(scalar(@{$ranking})/4);
+     my $num_students = scalar(@{$ranking});
+     my @BottomSet = map { $_->[&Apache::loncoursedata::RNK_student()];
+                       } @{$ranking}[0..$number_to_grab];
+     my @TopSet    =
+         map {
+             $_->[&Apache::loncoursedata::RNK_student()];
+           } @{$ranking}[-$number_to_grab..0];
+     if (! @BottomSet || (@BottomSet == 1 && $BottomSet[0] eq '') ||
+         ! @TopSet    || (@TopSet    == 1 && $TopSet[0]    eq '')) {
+         return 'nan';
+     }
+     my ($bottom_sum,$bottom_max) =
+         &Apache::loncoursedata::get_sum_of_scores($symb,$part,\@BottomSet,
+                                                   undef,$starttime,$endtime);
+     my ($top_sum,$top_max) =
+         &Apache::loncoursedata::get_sum_of_scores($symb,$part,\@TopSet,
+                                                   undef,$starttime,$endtime);
+     my $deg_of_disc;
+     if ($top_max == 0 || $bottom_max==0) {
+         $deg_of_disc = 'nan';
      } else {
-         $Ptr .= 'value="Show Legend" />'."\n";
+         $deg_of_disc = ($top_sum/$top_max) - ($bottom_sum/$bottom_max);
+     }
+     #&Apache::lonnet::logthis('    '.$top_sum.'/'.$top_max.
+     #                         ' - '.$bottom_sum.'/'.$bottom_max);
+     return $deg_of_disc;
+ }
+ ###############################################
+ ###############################################
+ ##
+ ## Compute KR-21
+ ##
+ ## To compute KR-21, you need the following information:
+ ##
+ ## K=the number of items in your test
+ ## M=the mean score on the test
+ ## s=the standard deviation of the scores on your test
+ ##
+ ## then:
+ ##
+ ## KR-21 rk= [K/(K-1)] * [1- (M*(K-M))/(K*s^2))]
+ ##
+ ###############################################
+ ###############################################
+ sub compute_sequence_statistics {
+     my ($seq) = @_;
+     my $symb = $seq->symb;
+     my @Resources;
+     my $part_count;
+     foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)) {
+         push (@Resources,$res->symb);
+         $part_count += scalar(@{$res->parts});
      }
-     $Ptr .= '</td><td align="left">';
+     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
-     $Ptr .= '<input type="submit" name="DisplayCSVFormat" ';
+     #
-     if($displayFormat eq 'Display CSV Format') {
+     # First compute statistics based on student scores
-         $Ptr .= 'value="Display Table Format" />'."\n";
+     my ($smin,$smax,$sMean,$sSTD,$scount,$sMAX) =
+         &Apache::loncoursedata::score_stats
+                     ([&Apache::lonstatistics::get_selected_sections()],
+                      [&Apache::lonstatistics::get_selected_groups()],
+                      $Apache::lonstatistics::enrollment_status,
+                      \@Resources,$starttime,$endtime,undef);
+     $SeqStat{$symb}->{'title'}  = $seq->compTitle;
+     $SeqStat{$symb}->{'scoremax'}  = $smax;
+     $SeqStat{$symb}->{'scoremin'}  = $smin;
+     $SeqStat{$symb}->{'scoremean'} = $sMean;
+     $SeqStat{$symb}->{'scorestd'}  = $sSTD;
+     $SeqStat{$symb}->{'scorecount'} = $scount;
+     $SeqStat{$symb}->{'max_possible'} = $sMAX;
+     #
+     # Compute statistics based on the number of correct problems
+     # 'correct' is taken to mean
+     my ($cmin,$cmax,$cMean,$cSTD,$ccount)=
+         &Apache::loncoursedata::count_stats
+         ([&Apache::lonstatistics::get_selected_sections()],
+          [&Apache::lonstatistics::get_selected_groups()],
+          $Apache::lonstatistics::enrollment_status,
+          \@Resources,$starttime,$endtime,undef);
+     my $K = $part_count;
+     my $kr_21;
+     if ($K > 1 && $cSTD > 0) {
+         $kr_21 =  ($K/($K-1)) * (1 - $cMean*($K-$cMean)/($K*$cSTD**2));
      } else {
-         $Ptr .= 'value="Display CSV Format" />'."\n";
+         $kr_21 = 'nan';
      }
-     $Ptr .= '</td></tr>';
+     $SeqStat{$symb}->{'countmax'} = $cmax;
-     return $Ptr;
+     $SeqStat{$symb}->{'countmin'} = $cmin;
+     $SeqStat{$symb}->{'countstd'} = $cSTD;
+     $SeqStat{$symb}->{'countmean'} = $cMean;
+     $SeqStat{$symb}->{'count'} = $ccount;
+     $SeqStat{$symb}->{'items'} = $K;
+     $SeqStat{$symb}->{'KR-21'}=$kr_21;
+     return;
  }
- sub ProblemStatisticsLegend {
-     my $Ptr = '';
-     $Ptr = '<table border="0">';
-     $Ptr .= '<tr><td>';
-     $Ptr .= '<b>#Stdnts</b></td>';
-     $Ptr .= '<td>Total number of students attempted the problem.';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>Tries</b></td>';
-     $Ptr .= '<td>Total number of tries for solving the problem.';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>Mod</b></td>';
-     $Ptr .= '<td>Largest number of tries for solving the problem by a student.';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>Mean</b></td>';
-     $Ptr .= '<td>Average number of tries. [ Tries / #Stdnts ]';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>#YES</b></td>';
-     $Ptr .= '<td>Number of students solved the problem correctly.';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>#yes</b></td>';
-     $Ptr .= '<td>Number of students solved the problem by override.';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>%Wrong</b></td>';
-     $Ptr .= '<td>Percentage of students who tried to solve the problem ';
-     $Ptr .= 'but is still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>DoDiff</b></td>';
-     $Ptr .= '<td>Degree of Difficulty of the problem.  ';
-     $Ptr .= '[ 1 - ((#YES+#yes) / Tries) ]';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>S.D.</b></td>';
-     $Ptr .= '<td>Standard Deviation of the tries.  ';
-     $Ptr .= '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1) ';
-     $Ptr .= 'where Xi denotes every student\'s tries ]';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>Skew.</b></td>';
-     $Ptr .= '<td>Skewness of the students tries.';
-     $Ptr .= '[(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]';
-     $Ptr .= '</td></tr><tr><td>';
-     $Ptr .= '<b>Dis.F.</b></td>';
-     $Ptr .= '<td>Discrimination Factor: A Standard for evaluating the ';
-     $Ptr .= 'problem according to a Criterion<br>';
-     $Ptr .= '<b>[Criterion to group students into %27 Upper Students - ';
-     $Ptr .= 'and %27 Lower Students]</b><br>';
-     $Ptr .= '<b>1st Criterion</b> for Sorting the Students: ';
-     $Ptr .= '<b>Sum of Partial Credit Awarded / Total Number of Tries</b><br>';
-     $Ptr .= '<b>2nd Criterion</b> for Sorting the Students: ';
-     $Ptr .= '<b>Total number of Correct Answers / Total Number of Tries</b>';
-     $Ptr .= '</td></tr>';
-     $Ptr .= '<tr><td><b>Disc.</b></td>';
-     $Ptr .= '<td>Number of Students had at least one discussion.';
-     $Ptr .= '</td></tr></table>';
-     return $Ptr;
- }
- #---- END Problem Statistics Web Page ----------------------------------------
+ =pod
+ =item ProblemStatisticsLegend
+ =over 4
+ =item #Stdnts
+ Total number of students attempted the problem.
+ =item Tries
+ Total number of tries for solving the problem.
+ =item Max Tries
+ Largest number of tries for solving the problem by a student.
+ =item Mean
+ Average number of tries. [ Tries / #Stdnts ]
+ =item #YES
+ Number of students solved the problem correctly.
+ =item #yes
+ Number of students solved the problem by override.
+ =item %Wrong
+ Percentage of students who tried to solve the problem
+ but is still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]
+ =item DoDiff
+ Degree of Difficulty of the problem.
+ [ 1 - ((#YES+#yes) / Tries) ]
+ =item S.D.
+ Standard Deviation of the tries.
+ [ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1)
+ where Xi denotes every student\'s tries ]
+ =item Skew.
+ Skewness of the students tries.
+ [(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]
+ =item Dis.F.
+ Discrimination Factor: A Standard for evaluating the
+ problem according to a Criterion<br>
+ =item [Criterion to group students into %27 Upper Students -
+ and %27 Lower Students]
+st Criterion for Sorting the Students:
+ Sum of Partial Credit Awarded / Total Number of Tries
+nd Criterion for Sorting the Students:
+ Total number of Correct Answers / Total Number of Tries
+ =item Disc.
+ Number of Students had at least one discussion.
+ =back
+ =cut
+ ############################################################
+ ############################################################
 ;
  __END__

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