--- loncom/interface/statistics/lonproblemstatistics.pm	2004/03/29 19:41:24	1.76
+++ loncom/interface/statistics/lonproblemstatistics.pm	2012/05/12 03:17:43	1.122.2.1
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonproblemstatistics.pm,v 1.76 2004/03/29 19:41:24 matthew Exp $
+# $Id: lonproblemstatistics.pm,v 1.122.2.1 2012/05/12 03:17:43 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -50,17 +50,21 @@ Excel files, and plots.
 package Apache::lonproblemstatistics;
 
 use strict;
-use Apache::lonnet();
+use Apache::lonnet;
 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:
@@ -69,13 +73,42 @@ my @StatsArray;
 ## header for plots created with Graph.pm, both of which more than likely do
 ## not support localization.
 ##
+#
+#
+##
+## 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.  NOT translated
+## 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',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'container',
              title  => 'Sequence or Folder',
@@ -83,23 +116,23 @@ my @Fields = (
              color  => '#FFFFE6',
              sortable => 'yes',
              selectable => 'no',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'title',
              title  => 'Title',
              align  => 'left',
              color  => '#FFFFE6',
              special  => 'link',
-             sortable => 'yes', 
+             sortable => 'yes',
              selectable => 'no',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
-           { name   => 'part', 
+           { name   => 'part',
              title  => 'Part',
              align  => 'left',
              color  => '#FFFFE6',
              selectable => 'no',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'num_students',
              title  => '#Stdnts',
@@ -110,7 +143,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Number of Students Attempting Problem',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'tries',
              title  => 'Tries',
@@ -121,7 +154,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Total Number of Tries',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'max_tries',
              title  => 'Max Tries',
@@ -132,7 +165,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Maximum Number of Tries',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'min_tries',
              title  => 'Min Tries',
@@ -143,7 +176,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Minumum Number of Tries',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'mean_tries',
              title  => 'Mean Tries',
@@ -154,7 +187,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Average Number of Tries',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'std_tries',
              title  => 'S.D. tries',
@@ -165,7 +198,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Standard Deviation of Number of Tries',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'skew_tries',
              title  => 'Skew Tries',
@@ -176,7 +209,7 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Skew of Number of Tries',
              selectable => 'yes',
-             selected => 'no',
+             defaultselected => 'no',
            },
            { name   => 'num_solved',
              title  => '#YES',
@@ -186,8 +219,8 @@ my @Fields = (
              sortable  => 'yes',
              graphable => 'yes',
              long_title => 'Number of Students able to Solve',
-             selectable => 'no',
-             selected => 'yes',
+             selectable => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'num_override',
              title  => '#yes',
@@ -198,7 +231,18 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Number of Students given Override',
              selectable => 'yes',
-             selected => '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',
@@ -207,9 +251,20 @@ my @Fields = (
              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',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'deg_of_diff',
              title  => 'DoDiff',
@@ -221,7 +276,7 @@ my @Fields = (
              long_title => 'Degree of Difficulty'.
                            '[ 1 - ((#YES+#yes) / Tries) ]',
              selectable => 'yes',
-             selected => 'yes',
+             defaultselected => 'yes',
            },
            { name   => 'deg_of_disc',
              title  => 'DoDisc',
@@ -232,7 +287,229 @@ my @Fields = (
              graphable => 'yes',
              long_title => 'Degree of Discrimination',
              selectable => 'yes',
-             selected => 'no',
+             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 => 'Minumum 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 => 'Minumum 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',
            },
 );
 
@@ -241,38 +518,66 @@ my %SelectedFields;
 sub parse_field_selection {
     #
     # Pull out the defaults
-    if (! defined($ENV{'form.fieldselections'})) {
-        $ENV{'form.fieldselections'} = [];
+    if (! defined($env{'form.fieldselections'})) {
+        $env{'form.fieldselections'} = [];
         foreach my $field (@Fields) {
             next if ($field->{'selectable'} ne 'yes');
-            if ($field->{'selected'} eq 'yes') {
-                push(@{$ENV{'form.fieldselections'}},$field->{'name'});
+            if ($field->{'defaultselected'} eq 'yes') {
+                push(@{$env{'form.fieldselections'}},$field->{'name'});
             }
         }
     }
     #
+    # Make sure the data we are plotting is there
+    my %NeededFields;
+    if (exists($env{'form.plot'}) && $env{'form.plot'} ne '' &&
+        $env{'form.plot'} ne 'none') {
+        if ($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 {
+            $NeededFields{$env{'form.plot'}}++;
+        }
+    }
+    #
     # This should not happen, but in case it does...
-    if (ref($ENV{'form.fieldselections'}) ne 'ARRAY') {
-        $ENV{'form.fieldselections'} = [$ENV{'form.fieldselections'}];
+    if (ref($env{'form.fieldselections'}) ne 'ARRAY') {
+        $env{'form.fieldselections'} = [$env{'form.fieldselections'}];
     }
     #
     # Set the field data and the selected fields (for easier checking)
     undef(%SelectedFields);
     foreach my $field (@Fields) {
-        next if ($field->{'selectable'} ne 'yes');
-        $field->{'selected'} = 'no';
-        foreach my $selection (@{$ENV{'form.fieldselections'}}) {
+        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'}}++;
             }
         }
     }
+    #
+    # Always show all the sequence statistics (for now)
+    foreach my $field (@SeqFields) {
+        $field->{'selected'} = 'yes';
+    }
     return;
 }
 
 sub field_selection_input {
-    my $Str = '<select name="fieldselections" multiple size="5">'."\n";
+    my $Str = '<select name="fieldselections" multiple="multiple" size="5">'."\n";
     $Str .= '<option value="all">all</option>'."\n";
     foreach my $field (@Fields) {
         next if ($field->{'selectable'} ne 'yes');
@@ -300,52 +605,49 @@ select sections, maps, and output.
 ###############################################
 ###############################################
 sub CreateInterface {
+    my ($r) = @_;
+    #
     &parse_field_selection();
+    #
     my $Str = '';
-    $Str .= &Apache::lonhtmlcommon::breadcrumbs
-        (undef,'Overall Problem Statistics','Statistics_Overall_Key');
-    $Str .= '<table cellspacing="5">'."\n";
-    $Str .= '<tr>';
-    $Str .= '<td align="center"><b>'.&mt('Sections').'</b></td>';
-    $Str .= '<td align="center"><b>'.&mt('Enrollment Status').'</b></td>';
-    $Str .= '<td align="center"><b>'.&mt('Sequences and Folders').'</b></td>';
-    $Str .= '<td align="center"><b>'.&mt('Statistics').'</b></td>';
-    $Str .= '<td rowspan="2">'.
-        &Apache::lonstathelpers::limit_by_time_form().'</td>';
-    $Str .= '</tr>'."\n";
+    $Str .= '<p>';
+    $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();
     #
-    $Str .= '<tr><td align="center">'."\n";
+    $Str .= &Apache::loncommon::start_data_table_row();
+    $Str .= '<td align="center" valign="top">'."\n";
     $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
-    $Str .= '</td><td align="center">';
+    $Str .= '</td><td align="center" valign="top">';
+    $Str .= &Apache::lonstatistics::GroupSelect('Group','multiple',5);
+    $Str .= '</td><td align="center" valign="top">';
     $Str .= &Apache::lonhtmlcommon::StatusOptions(undef,undef,5);
-    $Str .= '</td><td align="center">';
+    $Str .= '</td><td align="center" valign="top">';
     #
-    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>'.&field_selection_input();
-    $Str .= '</td></tr>'."\n";
-    $Str .= '</table>'."\n";
+    $Str .= &Apache::lonstatistics::map_select('Maps','multiple,all',5);
+    $Str .= '</td><td align="center" valign="top">';
+    $Str .= &field_selection_input();
+    $Str .= '</td><td align="center" valign="top">';
+    $Str .= &plot_dropdown();
+    $Str .= '</td>'."\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 .= '</p>';
     $Str .= '<input type="submit" name="GenerateStatistics" value="'.
         &mt('Generate Statistics').'" />';
-    $Str .= '&nbsp;'x5;
-    $Str .= 'Plot '.&plot_dropdown().('&nbsp;'x10);
-    $Str .= '<input type="submit" name="ClearCache" value="'.
-        &mt('Clear Caches').'" />';
-    $Str .= '&nbsp;'x5;
-    $Str .= '<input type="submit" name="UpdateCache" value="'.
-        &mt('Update Student Data').'" />';
-    $Str .= '&nbsp;'x5;
-    $Str .= '<input type="submit" name="Excel" value="'.
-        &mt('Produce Excel Output').'" />';
-    $Str .= '&nbsp;'x5;
+    $Str .= ('&nbsp;'x10);
+    #
     return $Str;
 }
 
@@ -362,14 +664,26 @@ Main interface to problem statistics.
 
 ###############################################
 ###############################################
+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');
+                               'Maps' => 'array',
+                               'fieldselections'=> 'array');
     &Apache::loncommon::store_course_settings('statistics',
                                               \%Saveable_Parameters);
     &Apache::loncommon::restore_course_settings('statistics',
@@ -379,30 +693,36 @@ sub BuildProblemStatisticsPage {
     #
     # Clear the package variables
     undef(@StatsArray);
+    undef(%SeqStat);
     #
     # Finally let the user know we are here
-    my $interface = &CreateInterface();
+    $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'}.
+    $r->print('<input type="hidden" name="sortby" value="'.$env{'form.sortby'}.
               '" />');
     #
-    if (! exists($ENV{'form.statsfirstcall'})) {
-        $r->print('<input type="hidden" name="statsfirstcall" value="yes" />');
-        $r->print('<h3>'.
+    my @CacheButtonHTML =
+        &Apache::lonstathelpers::manage_caches($r,'Statistics','stats_status');
+    my $Str;
+    foreach my $html (@CacheButtonHTML) {
+        $Str.=$html.('&nbsp;'x5);
+    }
+    #
+    $r->print($Str);
+    if (! exists($env{'form.firstrun'})) {
+        $r->print('<p class="LC_info"><b>'.
                   &mt('Press "Generate Statistics" when you are ready.').
-                  '</h3><p>'.
+                  '</b></p>'.
+                  '<p class="LC_info">'.
                   &mt('It may take some time to update the student data '.
-                      'for the first analysis.  Future analysis this session '.
-                      ' will not have this delay.').
+                      'for the first analysis. Future analysis this session '.
+                      'will not have this delay.').
                   '</p>');
+	&clean_up();
         return;
-    } elsif ($ENV{'form.statsfirstcall'} eq 'yes' || 
-             exists($ENV{'form.UpdateCache'}) ||
-             exists($ENV{'form.ClearCache'}) ) {
-        $r->print('<input type="hidden" name="statsfirstcall" value="no" />');
-        &Apache::lonstatistics::Gather_Student_Data($r);
-    } else {
-        $r->print('<input type="hidden" name="statsfirstcall" value="no" />');
     }
     $r->rflush();
     #
@@ -410,12 +730,31 @@ sub BuildProblemStatisticsPage {
     # it does not slow things down noticably.
     &Apache::loncoursedata::populate_weight_table();
     #
-    if (exists($ENV{'form.Excel'})) {
+    ($navmap,@sequences) =
+        &Apache::lonstatistics::selected_sequences_with_assessments();
+    if (! ref($navmap)) {
+        $r->print('<div class="LC_error">'.&mt('A course-wide error occurred.').'</div>'.
+                  '<h3>'.$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();
+        $r->print('<p>'.
+                  &Apache::lonstatistics::section_and_enrollment_description().
+                  '</p>');
         my $count = 0;
-        foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
-            $count += $seq->{'num_assess'};
+        foreach my $seq (@sequences) {
+            my @resources =
+                &Apache::lonstathelpers::get_resources($navmap,$seq);
+            $count += scalar(@resources);
         }
         if ($count > 10) {
             $r->print('<h2>'.
@@ -427,24 +766,47 @@ sub BuildProblemStatisticsPage {
             $r->rflush();
         }
         #
-        my $sortby = $ENV{'form.sortby'};
+        my $sortby = $env{'form.sortby'};
         $sortby = 'container' if (! defined($sortby) || $sortby =~ /^\s*$/);
-        my $plot = $ENV{'form.plot'};
+        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);
         }
     }
+    &clean_up();
     return;
 }
 
+sub output_sequence_statistics {
+    my ($r) = @_;
+    my $c=$r->connection();
+    $r->print('<h2>'.&mt('Sequence Statistics').
+	      &Apache::loncommon::help_open_topic('Statistics_Sequence').
+	      '</h2>');
+    $r->print(&Apache::loncommon::start_data_table().&Apache::loncommon::start_data_table_header_row());
+    $r->print(&sequence_html_header());
+    $r->print(&Apache::loncommon::end_data_table_header_row());
+    foreach my $seq (@sequences) {
+        last if ($c->aborted);
+        &compute_sequence_statistics($seq);
+        $r->print(&sequence_html_output($seq));
+    }
+    $r->print(&Apache::loncommon::end_data_table());
+    $r->rflush();
+    return;
+}
+
+
 ##########################################################
 ##########################################################
 ##
@@ -455,23 +817,22 @@ sub BuildProblemStatisticsPage {
 sub output_html_by_sequence {
     my ($r) = @_;
     my $c = $r->connection();
-    $r->print(&html_preamble());
+    $r->print('<br>'.&html_preamble());
     #
-    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
+    foreach my $seq (@sequences) {
         last if ($c->aborted);
-        next if ($seq->{'num_assess'} < 1);
-        $r->print("<h3>".$seq->{'title'}."</h3>".
-                  '<table border="0"><tr><td bgcolor="#777777">'."\n".
-                  '<table border="0" cellpadding="3">'."\n".
-                  '<tr bgcolor="#FFFFE6">'.
-                  &statistics_table_header('no container')."</tr>\n");
+        $r->print("<h3>".$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) {
-            $r->print('<tr>'.&statistics_html_table_data($data,
-                                                         'no container').
-                      "</tr>\n");
+            $r->print(&Apache::loncommon::start_data_table_row().
+                    &statistics_html_table_data($data,'no container').
+                    &Apache::loncommon::end_data_table_row()."\n");
         }
-        $r->print('</table>'."\n".'</table>'."\n");
+        $r->print(&Apache::loncommon::end_data_table()."\n");
         $r->rflush();
     }
     return;
@@ -481,29 +842,29 @@ sub output_html_stats {
     my ($r)=@_;
     &compute_all_statistics($r);
     $r->print(&html_preamble());
-    &sort_data($ENV{'form.sortby'});
+    &sort_data($env{'form.sortby'});
     #
     my $count=0;
     foreach my $data (@StatsArray) {
         if ($count++ % 50 == 0) {
-            $r->print("</table>\n</table>\n");
-            $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n".
-                      '<table border="0" cellpadding="3">'."\n".
-                      '<tr bgcolor="#FFFFE6">'.
-                      '<tr bgcolor="#FFFFE6">'.
-                      &statistics_table_header().
-                      "</tr>\n");
-        }
-        $r->print('<tr>'.&statistics_html_table_data($data)."</tr>\n");
+            $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("</table>\n</table>\n");
+    $r->print(&Apache::loncommon::end_data_table_row());
     return;
 }
 
 sub html_preamble {
     my $Str='';
     $Str .= "<h2>".
-        $ENV{'course.'.$ENV{'request.course.id'}.'.description'}.
+        $env{'course.'.$env{'request.course.id'}.'.description'}.
         "</h2>\n";
     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
     if (defined($starttime) || defined($endtime)) {
@@ -513,8 +874,8 @@ sub html_preamble {
                            &Apache::lonlocal::locallocaltime($endtime)
                            ).'</h3>';
     }
-    $Str .= "<h3>".&mt('Compiled on [_1]',
-                       &Apache::lonlocal::locallocaltime(time))."</h3>";
+    $Str .= "<p>".&mt('Compiled on [_1]',
+                       &Apache::lonlocal::locallocaltime(time))."</p>";
     return $Str;
 }
 
@@ -532,7 +893,7 @@ sub statistics_html_table_data {
     foreach my $field (@Fields) {
         next if ($options =~ /no $field->{'name'}/);
         next if ($field->{'selected'} ne 'yes');
-        $row .= '<td bgcolor="'.$field->{'color'}.'"';
+        $row .= '<td style="background-color:'.$field->{'color'}.'"';
         if (exists($field->{'align'})) {
             $row .= ' align="'.$field->{'align'}.'"';
             }
@@ -540,7 +901,7 @@ sub statistics_html_table_data {
         if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
             $row .= '<a href="'.$data->{$field->{'name'}.'.link'}.'">';
         }
-        if (exists($field->{'format'})) {
+        if (exists($field->{'format'}) && $data->{$field->{'name'}} !~ /[A-Z]/i) {
             $row .= sprintf($field->{'format'},$data->{$field->{'name'}});
         } else {
             $row .= $data->{$field->{'name'}};
@@ -583,6 +944,40 @@ sub statistics_table_header {
     return $header_row;
 }
 
+sub sequence_html_header {
+    my $Str .= '<tr>';
+    foreach my $field (@SeqFields) {
+#        next if ($field->{'selected'} ne 'yes');
+        $Str .= '<th bgcolor="'.$field->{'color'}.'"';
+        $Str .= '>'.$field->{'title'}.'</th>';
+    }
+    $Str .= '</tr>';
+    return $Str;
+}
+
+
+sub sequence_html_output {
+    my ($seq) = @_;
+    my $data = $SeqStat{$seq->symb};
+    my $row = '<tr>';
+    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 .= '</tr>'."\n";
+    return $row;
+}
+
 ####################################################
 ####################################################
 ##
@@ -593,7 +988,7 @@ sub statistics_table_header {
 sub make_plot {
     my ($r,$plot) = @_;
     &compute_all_statistics($r);
-    &sort_data($ENV{'form.sortby'});
+    &sort_data($env{'form.sortby'});
     if ($plot eq 'degrees') {
         &degrees_plot($r);
     } elsif ($plot eq 'tries statistics') {
@@ -623,7 +1018,7 @@ sub make_single_stat_plot {
     }
     #
     # Build up the data sets to plot
-    my @Labels; 
+    my @Labels;
     my @Data;
     my $max = 1;
     foreach my $data (@StatsArray) {
@@ -663,7 +1058,7 @@ sub degrees_plot {
     my $plot = '';
     my $ymax = 0;
     my $ymin = 0;
-    my @Disc; my @Diff; my @Labels;    
+    my @Disc; my @Diff; my @Labels;
     foreach my $data (@StatsArray) {
         push(@Labels,$data->{'problem_num'});
         my $disc = $data->{'deg_of_disc'};
@@ -710,6 +1105,11 @@ sub degrees_plot {
     my $diffdata .= '<data>'.join(',',@Labels).'</data>'.$/.
                     '<data>'.join(',',@Diff).'</data>'.$/;
     #
+    my $title = 'Degree of Discrimination\nand Degree of Difficulty';
+    if ($xmax > 50) {
+        $title = 'Degree of Discrimination and Degree of Difficulty';
+    }
+    #
     $plot=<<"END";
 <gnuplot 
     texfont="10"
@@ -720,7 +1120,7 @@ sub degrees_plot {
     align="center"
     border="on"
     transparent="on"
-    alttag="Sample Plot"
+    alttag="Degree of Discrimination and Degree of Difficulty Plot"
     samples="100"
     bgcolor="xffffff"
     height="$height"
@@ -729,7 +1129,7 @@ sub degrees_plot {
         pos="top right"
         title=""
         box="off" />
-    <title>Degree of Discrmination and Degree of Difficulty</title>
+    <title>$title</title>
     <axis xmin="0" ymin="$ymin" xmax="$xmax" ymax="$ymax" color="x000000" />
     <xlabel>Problem Number</xlabel>
     <curve 
@@ -748,7 +1148,7 @@ sub degrees_plot {
     </curve>
 </gnuplot>
 END
-    my $plotresult = 
+    my $plotresult =
         '<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
     $r->print($plotresult);
     return;
@@ -793,6 +1193,11 @@ sub tries_data_plot {
                           '<data>'.join(',',@Mean).'</data>'.$/.
                           '<data>'.join(',',@STD).'</data>'.$/;
     #
+    my $title = 'Mean and S.D. of Tries';
+    if ($xmax > 25) {
+        $title = 'Mean and Standard Deviation of Tries';
+    }
+    #
     $plot=<<"END";
 <gnuplot 
     texfont="10"
@@ -803,14 +1208,15 @@ sub tries_data_plot {
     align="center"
     border="on"
     transparent="on"
-    alttag="Sample Plot"
+    alttag="Mean and S.D of Tries Plot"
     samples="100"
     bgcolor="xffffff"
     height="$height"
     width="$width">
-    <title>Mean and S.D. of Tries</title>
+    <title>$title</title>
     <axis xmin="0" ymin="0" xmax="$xmax" ymax="$ymax" color="x000000" />
     <xlabel>Problem Number</xlabel>
+    <ylabel>Number of Tries</ylabel>
     <curve 
         linestyle="yerrorbars"
         name="S.D. Tries" 
@@ -827,7 +1233,7 @@ sub tries_data_plot {
     </curve>
 </gnuplot>
 END
-    my $plotresult = 
+    my $plotresult =
         '<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
     $r->print($plotresult);
     return;
@@ -836,22 +1242,22 @@ END
 sub plot_dropdown {
     my $current = '';
     #
-    if (defined($ENV{'form.plot'})) {
-        $current = $ENV{'form.plot'};
+    if (defined($env{'form.plot'})) {
+        $current = $env{'form.plot'};
     }
     #
     my @Additional_Plots = (
                             { graphable=>'yes',
                               name => 'degrees',
-                              title => 'DoDisc and DoDiff' },
+                              title => 'Difficulty Indexes' },
                             { graphable=>'yes',
                               name => 'tries statistics',
-                              title => 'Mean and S.D. of Tries' });
+                              title => 'Tries Statistics' });
     #
     my $Str= "\n".'<select name="plot" size="1">';
     $Str .= '<option name="none"></option>'."\n";
     $Str .= '<option name="none2">none</option>'."\n";
-    foreach my $field (@Fields,@Additional_Plots) {
+    foreach my $field (@Additional_Plots,@Fields) {
         if (! exists($field->{'graphable'}) ||
             $field->{'graphable'} ne 'yes') {
             next;
@@ -881,33 +1287,16 @@ sub Excel_output {
     &compute_all_statistics($r);
     my $c = $r->connection;
     return if ($c->aborted());
+    #
+    my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
     ##
     ## Create the excel workbook
-    my $filename = '/prtspool/'.
-        $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.
-        time.'_'.rand(1000000000).'.xls';
-    my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
-    #
-    # Create sheet
-    my $excel_workbook = Spreadsheet::WriteExcel->new('/home/httpd'.$filename);
-    #
-    # Check for errors
-    if (! defined($excel_workbook)) {
-        $r->log_error("Error creating excel spreadsheet $filename: $!");
-        $r->print(&mt("Problems creating new Excel file.  ".
-                  "This error has been logged.  ".
-                  "Please alert your LON-CAPA administrator."));
-        return 0;
-    }
-    #
-    # The excel spreadsheet stores temporary data in files, then put them
-    # together.  If needed we should be able to disable this (memory only).
-    # The temporary directory must be specified before calling 'addworksheet'.
-    # File::Temp is used to determine the temporary directory.
-    $excel_workbook->set_tempdir($Apache::lonnet::tmpdir);
+    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'};
+    my $sheetname = $env{'course.'.$env{'request.course.id'}.'.description'};
     if (length($sheetname) > 31) {
         $sheetname = substr($sheetname,0,31);
     }
@@ -920,28 +1309,17 @@ sub Excel_output {
     #
     # Put the course description in the header
     $excel_sheet->write($rows_output,$cols_output++,
-                   $ENV{'course.'.$ENV{'request.course.id'}.'.description'});
+                   $env{'course.'.$env{'request.course.id'}.'.description'},
+                        $format->{'h1'});
     $cols_output += 3;
     #
     # Put a description of the sections listed
     my $sectionstring = '';
-    my @Sections = @Apache::lonstatistics::SelectedSections;
-    if (scalar(@Sections) > 1) {
-        if (scalar(@Sections) > 2) {
-            my $last = pop(@Sections);
-            $sectionstring = "Sections ".join(', ',@Sections).', and '.$last;
-        } else {
-            $sectionstring = "Sections ".join(' and ',@Sections);
-        }
-    } else {
-        if ($Sections[0] eq 'all') {
-            $sectionstring = "All sections";
-        } else {
-            $sectionstring = "Section ".$Sections[0];
-        }
-    }
-    $excel_sheet->write($rows_output,$cols_output++,$sectionstring);
-    $cols_output += scalar(@Sections);
+    $excel_sheet->write($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;
@@ -957,45 +1335,59 @@ sub Excel_output {
         # See note above about lonlocal:locallocaltime
         $time_string .= 'Data collected before '.localtime($endtime).'.';
     }
+    if (defined($time_string)) {
+        $excel_sheet->write($rows_output,$cols_output++,$time_string);
+        $cols_output+= 5;
+    }
     #
     # Put the date in there too
     $excel_sheet->write($rows_output,$cols_output++,
                         'Compiled on '.localtime(time));
     #
-    $rows_output++; 
+    $rows_output++;
     $cols_output=0;
-    #
-    # Long Headers
-    foreach my $field (@Fields) {
-        next if ($field->{'name'} eq 'problem_num');
-        next if ($field->{'selected'} ne 'yes');
-        if (exists($field->{'long_title'})) {
+    ##
+    ## 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++,
-                                $field->{'long_title'});
-        } else {
-            $excel_sheet->write($rows_output,$cols_output++,'');
+                                $data->{$field->{'name'}},$fieldformat);
         }
+        $rows_output++;
+        $cols_output=0;
     }
+    ##
+    ## Resource Statistics
+    ##
     $rows_output++;
     $cols_output=0;
-    # Brief headers
-    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'});
-    }
-    $rows_output++;
+    &write_headers($excel_sheet,$format,\$rows_output,\$cols_output,
+                   \@Fields);
+    #
     foreach my $data (@StatsArray) {
         $cols_output=0;
         foreach my $field (@Fields) {
             next if ($field->{'selected'} ne 'yes');
             next if ($field->{'name'} eq 'problem_num');
+            my $fieldformat = undef;
+            if (exists($field->{'excel_format'})) {
+                $fieldformat = $format->{$field->{'excel_format'}};
+            }
             $excel_sheet->write($rows_output,$cols_output++,
-                                $data->{$field->{'name'}});
+                                $data->{$field->{'name'}},$fieldformat);
         }
         $rows_output++;
+        $cols_output=0;
     }
     #
     $excel_workbook->close();
@@ -1008,6 +1400,44 @@ sub Excel_output {
     return;
 }
 
+##
+## &write_headers
+##
+sub write_headers {
+    my ($excel_sheet,$format,$rows_output,$cols_output,$Fields) = @_;
+    ##
+    ## First the long titles
+    foreach my $field (@{$Fields}) {
+        next if ($field->{'name'} eq 'problem_num');
+        next if ($field->{'selected'} ne 'yes');
+        if (exists($field->{'long_title'})) {
+            $excel_sheet->write($$rows_output,${$cols_output},
+                                $field->{'long_title'},
+                                $format->{'bold'});
+        } else {
+            $excel_sheet->write($$rows_output,${$cols_output},'');
+        }
+        ${$cols_output}+= 1;
+    }
+    ${$cols_output} =0;
+    ${$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;
+}
+
 ##################################################
 ##################################################
 ##
@@ -1018,9 +1448,9 @@ sub Excel_output {
 sub compute_statistics_on_sequence {
     my ($seq) = @_;
     my @Data;
-    foreach my $res (@{$seq->{'contents'}}) {
-        next if ($res->{'type'} ne 'assessment');
-        foreach my $part (@{$res->{'parts'}}) {
+    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);
@@ -1038,9 +1468,9 @@ sub compute_all_statistics {
         return;
     }
     my $c = $r->connection;
-    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
+    foreach my $seq (@sequences) {
         last if ($c->aborted);
-        next if ($seq->{'num_assess'} < 1);
+        &compute_sequence_statistics($seq);
         &compute_statistics_on_sequence($seq);
     }
 }
@@ -1109,13 +1539,13 @@ sub sort_data {
 
 =item &get_statistics()
 
-Wrapper routine from the call to loncoursedata::get_problem_statistics.  
+Wrapper routine from the call to loncoursedata::get_problem_statistics.
 Calls lonstathelpers::get_time_limits() to limit the data set by time
 and &compute_discrimination_factor
 
 Inputs: $sequence, $resource, $part, $problem_num
 
-Returns: Hash reference with statistics data from 
+Returns: Hash reference with statistics data from
 loncoursedata::get_problem_statistics.
 
 =cut
@@ -1126,28 +1556,59 @@ sub get_statistics {
     my ($sequence,$resource,$part,$problem_num) = @_;
     #
     my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
-    my $symb = $resource->{'symb'};
-    my $courseid = $ENV{'request.course.id'};
+    my $symb = $resource->symb;
+    my $courseid = $env{'request.course.id'};
     #
     my $data = &Apache::loncoursedata::get_problem_statistics
-                        (\@Apache::lonstatistics::SelectedSections,
+                        ([&Apache::lonstatistics::get_selected_sections()],
+                         [&Apache::lonstatistics::get_selected_groups()],
                          $Apache::lonstatistics::enrollment_status,
                          $symb,$part,$courseid,$starttime,$endtime);
+    $data->{'symb'}        = $symb;
     $data->{'part'}        = $part;
     $data->{'problem_num'} = $problem_num;
-    $data->{'container'}   = $sequence->{'title'};
-    $data->{'title'}       = $resource->{'title'};
-    $data->{'title.link'}  = $resource->{'src'}.'?symb='.
-        &Apache::lonnet::escape($resource->{'symb'});
+    $data->{'container'}   = $sequence->compTitle;
+    $data->{'title'}       = $resource->compTitle;
+    $data->{'title.link'}  = $resource->src.'?symb='.
+        &escape($resource->symb);
     #
     if ($SelectedFields{'deg_of_disc'}) {
-        $data->{'deg_of_disc'} = 
+        $data->{'deg_of_disc'} =
             &compute_discrimination_factor($resource,$part,$sequence);
     }
+    #
+    # 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;
 }
 
-
 ###############################################
 ###############################################
 
@@ -1164,33 +1625,43 @@ Returns: integer between -1 and 1
 ###############################################
 ###############################################
 sub compute_discrimination_factor {
-    my ($resource,$part,$sequence) = @_;
+    my ($resource,$part,$seq) = @_;
+    my $symb = $resource->symb;
     my @Resources;
-    foreach my $res (@{$sequence->{'contents'}}) {
-        next if ($res->{'symb'} eq $resource->{'symb'});
-        push (@Resources,$res->{'symb'});
+    foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)){
+        next if ($res->symb eq $symb);
+        push (@Resources,$res->symb);
     }
     #
     # rank
-    my $ranking = 
+    my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+    my $ranking =
         &Apache::loncoursedata::rank_students_by_scores_on_resources
         (\@Resources,
-         \@Apache::lonstatistics::SelectedSections,
-         $Apache::lonstatistics::enrollment_status,undef);
+         [&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()]; 
+    my @BottomSet = map { $_->[&Apache::loncoursedata::RNK_student()];
                       } @{$ranking}[0..$number_to_grab];
-    my @TopSet    = 
-        map { 
-            $_->[&Apache::loncoursedata::RNK_student()]; 
-          } @{$ranking}[($num_students-$number_to_grab)..($num_students-1)];
-    my ($bottom_sum,$bottom_max) = 
-        &Apache::loncoursedata::get_sum_of_scores($resource,$part,\@BottomSet);
-    my ($top_sum,$top_max) = 
-        &Apache::loncoursedata::get_sum_of_scores($resource,$part,\@TopSet);
+    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';
@@ -1204,6 +1675,73 @@ sub compute_discrimination_factor {
 
 ###############################################
 ###############################################
+##
+## 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});
+    }
+    my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+    #
+    # First compute statistics based on student scores
+    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 {
+        $kr_21 = 'nan';
+    }
+    $SeqStat{$symb}->{'countmax'} = $cmax;
+    $SeqStat{$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;
+}
+
+
 
 =pod 
 
@@ -1264,111 +1802,6 @@ Number of Students had at least one disc
 
 =cut
 
-
-############################################################
-############################################################
-##
-##  How this all works:
-##     Statistics are computed by calling &get_statistics with the sequence,
-##     resource, and part id to run statistics on.  At various places within
-##     the loops which compute the statistics, as well as before and after 
-##     the entire process, subroutines can be called.  The subroutines are
-##     registered to the following hooks:
-##
-##         hook          subroutine inputs
-##     ----------------------------------------------------------
-##         pre           $r,$count
-##         pre_seq       $r,$count,$seq
-##         pre_res       $r,$count,$seq,$res
-##         calc          $r,$count,$seq,$res,$data
-##         post_res      $r,$count,$seq,$res
-##         post_seq      $r,$count,$seq
-##         post          $r,$count
-##
-##         abort         $r
-##
-##     subroutines will be called in the order in which they are registered.
-##   
-############################################################
-############################################################
-{
-
-my %hooks;
-my $aborted = 0;
-
-sub abort_computation {
-    $aborted = 1;
-}
-
-sub clear_hooks {
-    $aborted = 0;
-    undef(%hooks);
-}
-
-sub register_hook {
-    my ($hookname,$subref)=@_;
-    if ($hookname !~ /^(pre|pre_seq|pre_res|post|post_seq|post_res|calc)$/){
-        return;
-    }
-    if (ref($subref) ne 'CODE') {
-        &Apache::lonnet::logthis('attempt to register hook to non-code: '.
-                                 $hookname,' = '.$subref);
-    } else {
-        if (exists($hooks{$hookname})) {
-            push(@{$hooks{$hookname}},$subref);
-        } else {
-            $hooks{$hookname} = [$subref];
-        }
-    }
-    return;
-}
-
-sub run_hooks {
-    my $context = shift();
-    foreach my $hook (@{$hooks{$context}}) { 
-        if ($aborted && $context ne 'abort') {
-            last;
-        }
-        my $retvalue = $hook->(@_);
-        if (defined($retvalue) && $retvalue eq '0') {
-            $aborted = 1 if (! $aborted);
-        }
-    }
-}
-
-sub run_statistics {
-    my ($r) = @_;
-    my $count = 0;
-    &run_hooks('pre',$r,$count);
-    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
-        last if ($aborted);
-        next if ($seq->{'num_assess'}<1);
-        &run_hooks('pre_seq',$r,$count,$seq);
-        foreach my $res (@{$seq->{'contents'}}) {
-            last if ($aborted);
-            next if ($res->{'type'} ne 'assessment');
-            &run_hooks('pre_res',$r,$count,$seq,$res);            
-            foreach my $part (@{$res->{'parts'}}) {
-                last if ($aborted);
-                #
-                # This is where all the work happens
-                my $data = &get_statistics($seq,$res,$part,++$count);
-                &run_hooks('calc',$r,$count,$seq,$res,$part,$data); 
-            }
-            &run_hooks('post_res',$r,$count,$seq,$res);
-        }
-        &run_hooks('post_seq',$r,$count,$seq);
-    }
-    if ($aborted) {
-        &run_hooks('abort',$r);
-    } else {
-        &run_hooks('post',$r,$count);
-    }
-    return;
-}
-
-} # End of %hooks scope
-
 ############################################################
 ############################################################