--- loncom/interface/statistics/lonproblemstatistics.pm	2002/08/01 20:49:06	1.9
+++ loncom/interface/statistics/lonproblemstatistics.pm	2004/01/28 14:38:40	1.64
@@ -1,7 +1,6 @@
 # The LearningOnline Network with CAPA
-# (Publication Handler
 #
-# $Id: lonproblemstatistics.pm,v 1.9 2002/08/01 20:49:06 stredwic Exp $
+# $Id: lonproblemstatistics.pm,v 1.64 2004/01/28 14:38:40 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -26,677 +25,813 @@
 # http://www.lon-capa.org/
 #
 # (Navigate problems for statistical reports
-# YEAR=2001
-# 5/5,7/9,7/25/1,8/11,9/13,9/26,10/5,10/9,10/22,10/26 Behrouz Minaei
-# 11/1,11/4,11/16,12/14,12/16,12/18,12/20,12/31 Behrouz Minaei
-# YEAR=2002
-# 1/22,2/1,2/6,2/25,3/2,3/6,3/17,3/21,3/22,3/26,4/7,5/6 Behrouz Minaei
-# 5/12,5/14,5/15,5/19,5/26,7/16,7/25,7/29  Behrouz Minaei
 #
-###
+###############################################
+###############################################
 
-package Apache::lonproblemstatistics; 
+=pod
+
+=head1 NAME
+
+lonproblemstatistics
+
+=head1 SYNOPSIS
+
+Routines to present problem statistics to instructors via tables,
+Excel files, and plots.
+
+=over 4
+
+=cut
+
+###############################################
+###############################################
+
+package Apache::lonproblemstatistics;
 
 use strict;
 use Apache::lonnet();
+use Apache::loncommon();
 use Apache::lonhtmlcommon;
 use Apache::loncoursedata;
-use GDBM_File;
+use Apache::lonstatistics;
+use Apache::lonlocal;
+use Spreadsheet::WriteExcel;
+
+##
+## 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.
+##
+my @Fields = (
+           { name => 'problem_num',
+             title => 'P#',
+             align => 'right',
+             color => '#FFFFE6' },
+           { name   => 'container',
+             title  => 'Sequence or Folder',
+             align  => 'left',
+             color  => '#FFFFE6',
+             sortable => 'yes' },
+           { name   => 'title',
+             title  => 'Title',
+             align  => 'left',
+             color  => '#FFFFE6',
+             special  => 'link',
+             sortable => 'yes', },
+           { name   => 'part', 
+             title  => 'Part',
+             align  => 'left',
+             color  => '#FFFFE6',
+             },
+           { name   => 'num_students',
+             title  => '#Stdnts',
+             align  => 'right',
+             color  => '#EEFFCC',
+             format => '%d',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Number of Students Attempting Problem' },
+           { name   => 'tries',
+             title  => 'Tries',
+             align  => 'right',
+             color  => '#EEFFCC',
+             format => '%d',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Total Number of Tries' },
+           { name   => 'max_tries',
+             title  => 'Max Tries',
+             align  => 'right',
+             color  => '#DDFFFF',
+             format => '%d',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Maximum Number of Tries' },
+           { name   => 'mean_tries',
+             title  => 'Mean Tries',
+             align  => 'right',
+             color  => '#DDFFFF',
+             format => '%5.2f',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Average Number of Tries' },
+           { 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' },
+           { name   => 'skew_tries',
+             title  => 'Skew Tries',
+             align  => 'right',
+             color  => '#DDFFFF',
+             format => '%5.2f',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Skew of Number of Tries' },
+           { name   => 'deg_of_diff',
+             title  => 'DoDiff',
+             align  => 'right',
+             color  => '#DDFFFF',
+             format => '%5.2f',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Degree of Difficulty'.
+                           '[ 1 - ((#YES+#yes) / Tries) ]'},
+           { 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' },
+           { 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' },
+           { name   => 'per_wrong',
+             title  => '%Wrng',
+             align  => 'right',
+             color  => '#FFFFE6',
+             format => '%4.1f',
+             sortable  => 'yes',
+             graphable => 'yes',
+             long_title => 'Percent of students whose final answer is wrong' },
+);
+
+###############################################
+###############################################
 
+=pod 
 
-sub BuildProblemStatisticsPage {
-    my ($cacheDB, $students, $courseID, $c, $r)=@_;
-    my %cache;
-    #my %DoDiff;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
-    }
+=item &CreateInterface()
 
-    my $Ptr = '';
-    $Ptr .= '<table border="0"><tbody>';
-    $Ptr .= '<tr><td align="right"><b>Select Map</b></td>'."\n";
-    $Ptr .= '<td align="left">';
-    $Ptr .= &Apache::lonhtmlcommon::MapOptions(\%cache, 'ProblemStatistics',
-                                               'Statistics');
-    $Ptr .= '</td></tr>'."\n";
-    $Ptr .= '<tr><td align="right"><b>Sorting Type:</b></td>'."\n";
-    $Ptr .= '<td align="left">'."\n";
-    $Ptr .= &Apache::lonhtmlcommon::AscendOrderOptions(
-                                            $cache{'ProblemStatisticsAscend'}, 
-                                            'ProblemStatistics',
-                                            'Statistics');
-    $Ptr .= '</td></tr>'."\n";
-    $Ptr .= &ProblemStatisticsButtons($cache{'DisplayFormat'});
-    $Ptr .= '</table>';
-    $Ptr .= &ProblemStatisticsLegend();
-    $r->print($Ptr);
-
-    untie(%cache);
-    foreach (@$students) {
-        my $courseData = 
-            &Apache::loncoursedata::DownloadCourseInformation($_, $courseID);
-        last if ($c->aborted());
-        if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT,0640)) {
-            &Apache::loncoursedata::ProcessStudentData(\%cache, 
-                                                       $courseData, $_);
-            untie(%cache);
-        }
-    }
-    if($c->aborted()) { return; }
-
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
-    }
-    my %discriminant=();
-    my @list=();
-    my %Discuss=&Apache::loncoursedata::LoadDiscussion($courseID);
-    my $index=0;
-    foreach (@$students) {
-	$index++;
-	#&Apache::lonstatistics::Update_PrgWin(++$index,$r);
-        &ExtractStudentData(\%cache, $_, \@list,\%Discuss, $r, \%discriminant);
-    }
-    #&Apache::lonstatistics::Close_PrgWin($r);
- 
-    my ($upper, $lower) = &Discriminant(\%discriminant,$r);
-    my %Header = (0,"Homework Sets Order",1,"#Stdnts",2,"Tries",3,"Mod",
-                  4,"Mean",5,"#YES",6,"#yes",7,"%Wrng",8,"DoDiff",
-                  9,"S.D.",10,"Skew.",11,"D.F.1st",12,"D.F.2nd", 13, "Disc.");
-    my $color=&setbgcolor(0);
-    my %GraphDat= &BuildStatisticsTable(\%cache, $upper, $lower, \@list, 
-                                        \%Header, $students, $r, $color);
-    untie(%cache);
+Create the main intereface for the statistics page.  Allows the user to
+select sections, maps, and output.
+
+=cut
+
+###############################################
+###############################################
+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',
+     },
+     );
+
+sub CreateInterface {
+    my $Str = '';
+    $Str .= '<h2>Overall Problem Statistics'.
+        &Apache::loncommon::help_open_topic('Statistics_Overall_Key').
+        '</h2>'."\n";
+    $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('Output').'</b></td>';
+    $Str .= '</tr>'."\n";
+    #
+    $Str .= '<tr><td align="center">'."\n";
+    $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
+    $Str .= '</td><td align="center">';
+    $Str .= &Apache::lonhtmlcommon::StatusOptions(undef,undef,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);
+    $Str .= '</td><td>'."\n";
+    my ($html,$outputmode,$show) = 
+        &Apache::lonstatistics::CreateAndParseOutputSelector(
+                                            'statsoutputmode',
+                                            'HTML problem statistics grouped',
+                                            @OutputOptions);
+    $Str .= $html;
+    $Str .= '</td></tr>'."\n";
+    $Str .= '</table>'."\n";
+    $Str .= '<input type="submit" name="GenerateStatistics" value="'.
+        &mt('Generate Statistics').'" />';
+    $Str .= '&nbsp;'x5;
+    $Str .= '<input type="submit" name="ClearCache" value="'.
+        &mt('Clear Caches').'" />';
+    $Str .= '&nbsp;'x5;
+    return ($Str,$outputmode,$show);
 }
 
+###############################################
+###############################################
 
-#---- Problem Statistics Web Page ---------------------------------------
+=pod 
 
+=item &BuildProblemStatisticsPage()
 
-sub NumericSort {          
-    $a <=> $b;
-}
+Main interface to problem statistics.
 
+=cut
 
-sub CreateProblemStatisticsTableHeading {
-    my ($displayFormat,$sequenceSource,$sequenceTitle,$headings,$r)=@_;
-    if($displayFormat eq 'Display CSV Format') {
-        $r->print('<br>"'.$sequenceTitle.'","');
-        $r->print($sequenceSource.'"');
-	return;
-    }
-
-    $r->print('<br><a href="'.$sequenceSource.
-              '" target="_blank">'.$sequenceTitle.'</a>');
-
-    my $Result = "\n".'<table border=2><tr><th>P#</th>'."\n";
-    for(my $nIndex=0; $nIndex < (scalar (keys %$headings)); $nIndex++) { 
-	$Result .= '<th>'.'<input type="submit" name="';
-        $Result .= 'ProblemStatisticsHeading" value="';
-        $Result .= $headings->{$nIndex}.'" />'.'</th>'."\n";
+###############################################
+###############################################
+sub BuildProblemStatisticsPage {
+    my ($r,$c)=@_;
+    #
+    my %Saveable_Parameters = ('Status' => 'scalar',
+                               'statsoutputmode' => 'scalar',
+                               'Section' => 'array',
+                               'StudentData' => 'array',
+                               'Maps' => 'array');
+    &Apache::loncommon::store_course_settings('statistics',
+                                              \%Saveable_Parameters);
+    &Apache::loncommon::restore_course_settings('statistics',
+                                                \%Saveable_Parameters);
+    #
+    &Apache::lonstatistics::PrepareClasslist();
+    #
+    my ($interface,$output_mode,$show) = &CreateInterface();
+    $r->print($interface);
+    $r->print('<input type="hidden" name="statsfirstcall" value="no" />');
+    $r->print('<input type="hidden" name="sortby" value="'.$ENV{'form.sortby'}.
+              '" />');
+    $r->print('<input type="hidden" name="plot" value="" />');
+    if (! exists($ENV{'form.statsfirstcall'})) {
+        return;
+    }
+    #
+    &Apache::lonstatistics::Gather_Student_Data($r);
+    #
+    #
+    if ($output_mode eq 'html') {
+        $r->print("<h2>".
+                  $ENV{'course.'.$ENV{'request.course.id'}.'.description'}.
+                  "</h2>\n");
+        $r->print("<h3>".localtime(time)."</h3>");
+        $r->rflush();
+        if ($show eq 'grouped') {
+            &output_html_grouped_by_sequence($r);
+        } elsif ($show eq 'ungrouped') {
+            &output_html_ungrouped($r);
+        }
+    } elsif ($output_mode eq 'excel') {
+        $r->print('<h2>'.&mt('Preparing Excel Spreadsheet').'</h2>');
+        &output_excel($r);
+    } else {
+        $r->print('<h1>'.&mt('Not implemented').'</h1>');
     }
-    $Result .= "\n".'</tr>'."\n";    
-    $r->print($Result);
-    $r->rflush();
+    return;
 }
 
-sub CloseTable {
-    my ($cache,$r)=@_;
-    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
-	return;
-    }    
-    $r->print("\n".'</table>'."\n");
-    $r->rflush();
-}
+###############################################
+###############################################
 
+=pod 
 
- 
-# ------ Dump the Student's DB file and handling the data for statistics table 
-sub ExtractStudentData {
-    my ($cache,$name,$list,$Discuss,$r,$discriminant)=@_;
-    my $totalTries = 0;
-    my $totalAwarded = 0;
-    my $spent=0;
-    my $spent_yes=0;
-    my $TotDiscuss=0;
-    my $TotalOpend = 0;
-    my $ProbSolved = 0;
-    my $ProbTot = 0;
-    my $TotFirst = 0;
-    my $TimeTot = 0;
-    my $Discussed=0;
-    my $discrim='';
-    my $tempSequenceOrder=100;
-
-#$Apache::lonxml::debug=1;
-#&Apache::lonhomework::showhash(%$cache);
-#$Apache::lonxml::debug=0;
-
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-	my $tempProblemOrder=100;
-        if($cache->{'ProblemStatisticsMaps'} ne 'All Maps'  &&
-           $cache->{'ProblemStatisticsMaps'} ne $cache->{$sequence.':title'}) {
-#	    $r->print("<br>sequences=$cache->{'orderedSequences'}");
-#	    $r->print("<br>".$cache->{$sequence.':title'});
-            next;
-        }
-	$tempSequenceOrder++;
-
-        #$discrim .= '&';
-        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
-#	    $r->print("<br>problems=$cache->{$sequence.':problems'}");
-            my $problem = $cache->{$problemID.':problem'};
-#	    $r->print("<br>$problemID === $problem");
-            my $LatestVersion = $cache->{$name.':version:'.$problem};
-	    # Output dashes for all the parts of this problem if there
-            # is no version information about the current problem.
-            #if(!$LatestVersion) {
-            #    foreach my $part (split(/\:/,$cache->{$sequence.':'.
-            #                                          $problemID.
-            #                                          ':parts'})) {
-            #        $codes    .= "-,";
-            #        $attempts .= "0,"; 
-            #    }
-            #    next;
-            #}
-
-            my %partData=undef;
-	    $partData{'count'}=0;
-            # Initialize part data, display skips correctly
-            # Skip refers to when a student made no submissions on that
-            # part/problem.
-            foreach my $part (split(/\:/,$cache->{$sequence.':'.
-                                                  $problemID.
-                                                  ':parts'})) {
-		$tempProblemOrder++;
-		$partData{'count'}++;
-#		$r->print("<br>parts=$cache->{$sequence.':'.$problemID.':parts'}");
-                $partData{$part.':order'}=$tempProblemOrder;
-                $partData{$part.':tries'}=0;
-                $partData{$part.':code'}='-';
-            }
+=item &output_html_grouped_by_sequence()
 
-            # Looping through all the versions of each part, starting with the
-            # oldest version.  Basically, it gets the most recent 
-            # set of grade data for each part.
-	    for(my $Version=1; $Version<=$LatestVersion; $Version++) {
-		foreach my $part (split(/\:/,$cache->{$sequence.':'.
-                                                      $problemID.
-                                                      ':parts'})) {
-
-                    if(!defined($cache->{$name.":$Version:$problem".
-                                               ":resource.$part.solved"})) {
-                        # No grade for this submission, so skip
-                        next;
-                    }
+Presents the statistics data as an html table organized by the order
+the assessments appear in the course.
 
-                    my $tries=0;
-                    my $time=0;
-                    my $awarded=0;
-		    $Discussed=0;
-                    my $code='-';
-
-                    $awarded = $cache->{"$name:$Version:$problem:resource.".
-                                        "$part.awarded"};
-                    $partData{$part.':awarded'} = ($awarded) ? $awarded : 0;
-                    $totalAwarded += $awarded;
-
-                    $tries = $cache->{"$name:$Version:$problem".
-                                      ":resource.$part.tries"};
-                    $partData{$part.':tries'} = ($tries) ? $tries : 0;
-                    $partData{$part.':wrong'} = $partData{$part.':tries'};
-                    $totalTries += $tries;
-
-                    my $val = $cache->{$name.":$Version:$problem".
-                                       ":resource.$part.solved"};
-                    if    ($val eq 'correct_by_student')   {$code = 'C';} 
-                    elsif ($val eq 'correct_by_override')  {$code = 'O';}
-                    elsif ($val eq 'incorrect_attempted')  {$code = 'I';} 
-                    elsif ($val eq 'incorrect_by_override'){$code = 'I';}
-                    elsif ($val eq 'excused')              {$code = 'x';}
-                    $partData{$part.':code'}=$code;
-                    if($partData{$part.':wrong'} ne 0 && 
-                       ($code eq 'C' || $code eq 'O')) {
-                        $partData{$part.':wrong'}--;
-                    }
-                }
+=cut
+
+###############################################
+###############################################
+sub output_html_grouped_by_sequence {
+    my ($r) = @_;
+    my $problem_num = 0;
+    #$r->print(&ProblemStatisticsLegend());
+    foreach my $sequence (&Apache::lonstatistics::Sequences_with_Assess()) {
+        next if ($sequence->{'num_assess'}<1);
+        $r->print("<h3>".$sequence->{'title'}."</h3>");
+        $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+        $r->print('<table border="0" cellpadding="3">'."\n");
+        $r->print('<tr bgcolor="#FFFFE6">');
+        my $Str = &statistics_table_header('no container no plots');
+        $r->print('<tr bgcolor="#FFFFE6">'.$Str."</tr>\n");
+        foreach my $resource (@{$sequence->{'contents'}}) {
+            next if ($resource->{'type'} ne 'assessment');
+            foreach my $part (@{$resource->{'parts'}}) {
+                $problem_num++;
+                my $data = &get_statistics($sequence,$resource,$part,
+                                           $problem_num);
+                my $option = '';
+                $r->print('<tr>'.&statistics_html_table_data($data,
+                                                             'no container').
+                          "</tr>\n");
             }
+        }
+        $r->print("</table>\n");
+        $r->print("</td></tr></table>\n");
+        $r->rflush();
+    }
+    #
+    return;
+}
 
-#$Apache::lonxml::debug=1;
-#&Apache::lonhomework::showhash(%partData);
-#$Apache::lonxml::debug=0;
-
-            # Loop through all the parts for the current problem in the 
-            # correct order and prepare the output
-	    my $partCounter=0;
-            foreach (split(/\:/,$cache->{$sequence.':'.$problemID.
-                                         ':parts'})) {
-		$partCounter++;
-                my $Yes = 0;
-                if($partData{$_.':code'} eq 'C' || 
-                   $partData{$_.':code'} eq 'O') {
-                    $Yes=1;
-                }
-                my $pOrder=$partData{$_.':order'};
-                my $ptr = $tempSequenceOrder.':'.$pOrder.':'.$problemID;
+###############################################
+###############################################
 
-                if($partData{'count'} > 1) {
-                    $ptr .= "*(part $_)";
-                }
-                #if($partCounter > 1) {
-                    $discrim .= '&';
-                #}
-
-		my ($pr_no,$dod)=split('&',$ptr);
-#		my $DoDiff=$DoDiff->{$dod};
-#               $r->print('<br>'.$name.'---'.$ptr.'==='.$DoDiff);
-
-                my $Fac = ($partData{$_.':tries'}) ? 
-                    ($partData{$_.':awarded'}/$partData{$_.':tries'}) : 0;
-                my $DisF;
-                if($Fac > 0 &&  $Fac < 1) { 
-                    $DisF = sprintf( "%.4f", $Fac );
-                } else {
-                    $DisF = $Fac;
-                }
+=pod 
 
-                if ($Discuss->{"$name:$problem"}) {
-		    $TotDiscuss++;
-                    $Discussed=1;
-                }
-                my $time = $cache->{"$name:$LatestVersion:$problem:timestamp"};
-                $discrim .= $tempSequenceOrder.'@'.$pOrder.'='.$DisF.'+'.$Yes;
-                $ptr .= '&'.$partData{$_.':tries'}.
-                        '&'.$partData{$_.':wrong'}.
-                        '&'.$partData{$_.':code'};
-                push (@$list, $ptr."&$Discussed");
-#                $r->print('<br>'.$_.$name.'---'.$ptr);
-		
-####		if ($DoDiff>0.85) {
+=item &output_html_ungrouped()
 
-                $TimeTot += $time;
+Presents the statistics data in a single html table which can be sorted by
+different columns.
 
-                if ($Yes==1 && $partData{$_.':tries'}==1) {
-		    $TotFirst++;
-                }
-#		my $Acts= $Activity->{$name.':'.$problem};
-#		if ($Acts) {
-#		    my $Pt=&ProcAct( $Acts, $time );
-		    #my ($spe,$beg) = split(/\+/,$Pt);
-#                    my $spe= $Pt;
-#		    if ($Yes==1) {$spent_yes += $spe;}
-#		    $spent += $spe;
-		    #$Beg += $beg;
-#                   $r->print('<br>'.$name.'---'.$problem.'---'.$spe);
-#		}
-		$TotalOpend++;
-		$ProbTot++;
+=cut
 
-                $tempProblemOrder++;
+###############################################
+###############################################
+sub output_html_ungrouped {
+    my ($r,$option) = @_;
+    #
+    if (exists($ENV{'form.plot'}) && $ENV{'form.plot'} ne '') {
+        &plot_statistics($r,$ENV{'form.plot'});
+    }
+    #
+    my $problem_num = 0;
+    my $show_container = 0;
+    my $show_part = 0;
+    #$r->print(&ProblemStatisticsLegend());
+    my $sortby = undef;
+    foreach my $field (@Fields) {
+        if ($ENV{'form.sortby'} eq $field->{'name'}) {
+            $sortby = $field->{'name'};
+        }
+    }
+    if (! defined($sortby) || $sortby eq '' || $sortby eq 'problem_num') {
+        $sortby = 'container';
+    }
+    # If there is more than one sequence, list their titles
+    my @Sequences = &Apache::lonstatistics::Sequences_with_Assess();
+    if (@Sequences < 1) {
+        $option .= ' no container';
+    }
+    #
+    # Compile the data
+    my @Statsarray;
+    foreach my $sequence (@Sequences) {
+        next if ($sequence->{'num_assess'}<1);
+        foreach my $resource (@{$sequence->{'contents'}}) {
+            next if ($resource->{'type'} ne 'assessment');
+            foreach my $part (@{$resource->{'parts'}}) {
+                $problem_num++;
+                my $data = &get_statistics($sequence,$resource,$part,
+                                           $problem_num);
+                $show_part = 1 if ($part ne '0');
+                #
+                push (@Statsarray,$data);
             }
         }
     }
-    my $pstr;
-    if($totalTries) {
-	my $DisFac = ($totalAwarded/$totalTries);
-	my $DisFactor = sprintf( "%.4f", $DisFac );
-        my $TS = sprintf( "%.2f", $spent );
-        my $TS_yes = sprintf( "%.2f", $spent_yes );
-	$pstr=$DisFactor.':'.$name.':'.$ProbTot.':'.$TotalOpend.':'.
-              $totalTries.':'.$ProbSolved.':'.$TotFirst.':'.
-              $TS_yes.':'.$TS.':'.$TotDiscuss;
-	(%$discriminant)->{$pstr}=$discrim;
+    #
+    # Sort the data
+    my @OutputOrder;
+    if ($sortby eq 'container') {
+        @OutputOrder = @Statsarray;
+    } else {
+        # $sortby is already defined, so we can charge ahead
+        if ($sortby =~ /^(title|part)$/i) {
+            # Alpha comparison
+            @OutputOrder = sort {
+                lc($a->{$sortby}) cmp lc($b->{$sortby}) ||
+                    lc($a->{'title'}) cmp lc($b->{'title'}) ||
+                        lc($a->{'part'}) cmp lc($b->{'part'});
+            } @Statsarray;
+        } else {
+            # Numerical comparison
+            @OutputOrder = sort {
+                my $retvalue = 0;
+                if ($b->{$sortby} eq 'nan') {
+                    if ($a->{$sortby} ne 'nan') {
+                        $retvalue = -1;
+                    } else {
+                        $retvalue = 0;
+                    }
+                }
+                if ($a->{$sortby} eq 'nan') {
+                    if ($b->{$sortby} ne 'nan') {
+                        $retvalue = 1;
+                    }
+                }
+                if ($retvalue eq '0') {
+                    $retvalue = $b->{$sortby} <=> $a->{$sortby} ||
+                                lc($a->{'title'}) <=> lc($b->{'title'}) ||
+                                lc($a->{'part'})  <=> lc($b->{'part'});
+                }
+                $retvalue;
+            } @Statsarray;
+        }
+    }
+    $option .= 'no part' if (! $show_part);
+    my $num_output = 0;
+    #
+    # output the headers
+    $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+    $r->print('<table border="0" cellpadding="3">'."\n");
+    my $Str = &statistics_table_header($option.' sortable');
+    $r->print('<tr bgcolor="#FFFFE6">'.$Str."</tr>\n");
+    #
+    foreach my $rowdata (@OutputOrder) {
+        $num_output++;
+        if ($num_output % 25 == 0) {
+            $r->print("</table>\n</td></tr></table>\n");
+            #
+            $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+            $r->print('<table border="0" cellpadding="3">'."\n");
+            my $Str = &statistics_table_header($option.' sortable');
+            $r->print('<tr bgcolor="#FFFFE6">'.$Str."</tr>\n");
+            $r->rflush();
+        }
+        $r->print('<tr>'.&statistics_html_table_data($rowdata,$option).
+                  "</tr>\n");
     }
+    $r->print("</table>\n");
+    $r->print("</td></tr></table>\n");
+    $r->rflush();
+    #
+    return;
 }
 
+###############################################
+###############################################
 
-=pod
-sub MySort {          
-    if ( $Pos > 0 ) {
-	if ($ENV{'form.order'} eq 'Descending') {$b <=> $a;}
-	else { $a <=> $b; }
-    }
-    else {
-	if ($ENV{'form.order'} eq 'Descending') {$b cmp $a;}
-	else { $a cmp $b; }
+=pod 
+
+=item &output_excel()
+
+Presents the statistical data in an Excel 95 compatable spreadsheet file.
+
+=cut
+
+###############################################
+###############################################
+sub output_excel {
+    my ($r) = @_;
+    my $filename = '/prtspool/'.
+        $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.
+            time.'_'.rand(1000000000).'.xls';
+    #
+    my $excel_workbook = undef;
+    my $excel_sheet = undef;
+    #
+    my $rows_output = 0;
+    my $cols_output = 0;
+    #
+    # Create sheet
+    $excel_workbook = Spreadsheet::WriteExcel->new('/home/httpd'.$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 ;
+    }
+    #
+    # 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);
+    #
+    # Add a worksheet
+    my $sheetname = $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
+    if (length($sheetname) > 31) {
+        $sheetname = substr($sheetname,0,31);
+    }
+    $excel_sheet = $excel_workbook->addworksheet(
+                       &Apache::loncommon::clean_excel_name($sheetname)
+                                                 );
+    #
+    # Put the course description in the header
+    $excel_sheet->write($rows_output,$cols_output++,
+                   $ENV{'course.'.$ENV{'request.course.id'}.'.description'});
+    $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);
+    #
+    # Put the date in there too
+    $excel_sheet->write($rows_output,$cols_output++,
+                        'Compiled on '.localtime(time));
+    #
+    $rows_output++; 
+    $cols_output=0;
+    #
+    # Long Headersheaders
+    foreach my $field (@Fields) {
+        next if ($field->{'name'} eq 'problem_num');
+        if (exists($field->{'long_title'})) {
+            $excel_sheet->write($rows_output,$cols_output++,
+                                $field->{'long_title'});
+        } else {
+            $excel_sheet->write($rows_output,$cols_output++,'');
+        }
+    }
+    $rows_output++;
+    $cols_output=0;
+    # Brief headers
+    foreach my $field (@Fields) {
+        next if ($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 the data
+    my $problem_num=0;
+    foreach my $sequence (&Apache::lonstatistics::Sequences_with_Assess()) {
+        next if ($sequence->{'num_assess'}<1);
+        foreach my $resource (@{$sequence->{'contents'}}) {
+            next if ($resource->{'type'} ne 'assessment');
+            foreach my $part (@{$resource->{'parts'}}) {
+                $cols_output=0;
+                $problem_num++;
+                my $data = &get_statistics($sequence,$resource,$part,
+                                           $problem_num);
+                #
+                if (!defined($part) || $part eq '') {
+                    $part = ' ';
+                }
+                foreach my $field (@Fields) {
+                    next if ($field->{'name'} eq 'problem_num');
+                    $excel_sheet->write($rows_output,$cols_output++,
+                                        $data->{$field->{'name'}});
+                }
+                $rows_output++;
+            }
+        }
     }
+    #
+    # Write the excel file
+    $excel_workbook->close();
+    # Tell the user where to get their excel file
+    $r->print('<br />'.
+              '<a href="'.$filename.'">'.
+              &mt('Your Excel Spreadsheet').'</a>'."\n");
+    $r->rflush();
+    return;
 }
-=cut
 
+###############################################
+###############################################
 
-sub BuildStatisticsTable {
-    my ($cache,$upper,$lower,$list,$headings,$students,$r,$color)=@_;
-    my $NoElements = scalar @$list;
-    my @List=sort(@$list);
-
-#6666666
-#    my $file="/home/httpd/perl/tmp/183d.txt";
-#    open(OUT, ">$file");
-#6666666
-##     &Apache::lonstatistics::Create_PrgWin($r);
-##777777
-##    my (%Activity) = &LoadActivityLog();
-##    $r->print('<script>popwin.document.popremain.remaining.value="'.
-##              'Loading Discussion...";</script>');
-##    my ($doDiffFile) = &LoadDoDiffFile();
-
-##777777
-##    $Str .= &Classify($discriminantFactor, $students);
-
-    my $p_count = 0;
-    my $dummy;
-    my $p_val;
-    my $ResId;
-    my %GraphDat;
-    my $cIdx=0;
-
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-        if($cache->{'ProblemStatisticsMaps'} ne 'All Maps'  &&
-           $cache->{'ProblemStatisticsMaps'} ne $cache->{$sequence.':title'}) {
-            next;
-        }
-        &CreateProblemStatisticsTableHeading($cache->{'DisplayFormat'}, 
-                                             $cache->{$sequence.':source'},
-                                             $cache->{$sequence.':title'}, 
-                                             $headings,$r);
-	my ($tar,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,
-                                                   $List[$cIdx]);
-        my ($SqOrd,$PrOrd,$Prob)=split(/\:/,$tar);
-	$sequence+=100;
-	while ($SqOrd==$sequence && $cIdx<$NoElements) {
-	    my %storestats=();
-	    my $pOrd=$PrOrd;
-	    my $Temp = $Prob;
-	    my $MxTries = 0;
-	    my $TotalTries = 0;
-	    my $YES = 0;
-	    my $Incorrect = 0;
-	    my $Override = 0;
-	    my $StdNo = 0;
-	    my $DiscNo=0;
-	    my @StdLst;
-	    while ($pOrd==$PrOrd && $cIdx<$NoElements)
-	    {
-		$cIdx++;
-		$StdNo++;
-		$StdLst[ $StdNo ] = $Tries;
-		$TotalTries += $Tries;
-		if ( $MxTries < $Tries ) { $MxTries = $Tries; } 
-		if ( $Code eq 'C' ){ $YES++; }
-		elsif( $Code eq 'I' ) { $Incorrect++; }
-		elsif( $Code eq 'O' ) { $Override++; }
-		elsif( $Code eq '-' ) { $StdNo--; }
-		($tar,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,
-                                                     $List[$cIdx]);
-	        ($SqOrd,$PrOrd,$Prob)=split(/\:/,$tar);
-	    }
-
-	    $p_count++;
-	    my $Dummy;
-	    ($ResId,$Dummy)=split(/\*/,$Temp);
-
-######################
-	    $Temp = '<a href="'.$cache->{$ResId.':source'}.
-                '" target="_blank">'.$cache->{$ResId.':title'}.$Dummy.'</a>';
-
-	    #$r->print('<br>rid='.$ResId);
-	    #$r->print('<br>src='.$cache->{$ResId.':source'});
-	    #$r->print('<br>tit='.$cache->{$ResId.':title'});
-
-	    my $res = &Apache::lonnet::declutter($cache->{$ResId.':source'});
-	    my $urlres=$res;
-
-	    $ResId=~/(\d+)\.(\d+)/;
-	    my $Map = &Apache::lonnet::declutter( $cache->{'map_id_'.$1} );
-	    $urlres=$Map;
-#######################
-
-#	    $res = '<a href="'.$cache->{'src_'.$ResId}.'">'.$res.'</a>';
-	    #$Map = '<a href="'.$Map.'">'.$res.'</a>';
-
-#------------------------ Compute the Average of Tries about one problem
-	    my $Average = ($StdNo) ? $TotalTries/$StdNo : 0;
-
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___timestamp'}=time;
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___stdno'}=$StdNo;
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___avetries'}=$Average;
-   
-#-------------------------------- Compute percentage of Wrong tries
-	    my $Wrong = ( $StdNo ) ? 100 * ( $Incorrect / $StdNo ) : 0;
-
-#-------------------------------- Compute Standard Deviation
-	    my $StdDev = 0; 
-	    if ( $StdNo > 1 ) {
-		for ( my $n = 0; $n < $StdNo; $n++ ) {
-		    my $Dif = $StdLst[ $n ]-$Average;
-		    $StdDev += $Dif*$Dif;
-		} 
-		$StdDev /= ( $StdNo - 1 );
-		$StdDev = sqrt( $StdDev );
-	    }
-
-#-------------------------------- Compute Degree of Difficulty
-	    my $DoDiff = 0;
-	    if( $TotalTries > 0 ) {
-		$DoDiff = 1 - ( ( $YES + $Override ) / $TotalTries );
-#	    $DoDiff =  ($TotalTries)/($YES + $Override+ 0.1);	    
-	    }
-       
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___difficulty'}=$DoDiff;
-
-#-------------------------------- Compute the Skewness
-	    my $Skewness = 0;
-	    my $Sum = 0; 
-	    if ( $StdNo > 0 && $StdDev > 0 ) {
-		for ( my $n = 0; $n < $StdNo; $n++ ) {
-		    my $Dif = $StdLst[ $n ]-$Average;
-		    $Skewness += $Dif*$Dif*$Dif;
-		} 
-		$Skewness /= $StdNo;
-		$Skewness /= $StdDev*$StdDev*$StdDev;
-	    }
-
-#--------------------- Compute the Discrimination Factors
-            my ($Up1,$Up2)=split(/\:/,$upper->{$sequence.'@'.$pOrd});
-	    my ($Lw1,$Lw2)=split(/\:/,$lower->{$sequence.'@'.$pOrd});
-
-	    my $Dis1 = $Up1 - $Lw1;
-	    my $Dis2 = $Up2 - $Lw2;
-	    my $_D1 = sprintf("%.2f", $Dis1);
-	    my $_D2 = sprintf("%.2f", $Dis2);
-
-#-----------------  Some restition in presenting the float numbers
-	    my $Avg = sprintf( "%.2f", $Average );
-	    my $Wrng = sprintf( "%.1f", $Wrong );
-	    my $SD = sprintf( "%.1f", $StdDev );
-	    my $DoD = sprintf( "%.2f", $DoDiff );
-	    my $Sk = sprintf( "%.1f", $Skewness );
-	    my $join = $Prob.'&'.$Temp.'&'.$StdNo.'&'.
-                       $TotalTries.'&'.$MxTries.'&'.$Avg.'&'.
-                       $YES.'&'.$Override.'&'.$Wrng.'&'.$DoD.'&'.
-		       $SD.'&'.$Sk.'&'.$_D1.'&'.$_D2.'&'.
-                       $DiscNo.'&'.$Prob;
-##8888	    $CachData{($p_count-1)}=$join;
-
-#6666666
-#	    $r->print('<br>'.$out.'&'.$DoD);
-#            print (OUT $out.'@'.$DoD.'&');
-#6666666
-
-	    $urlres=~/^(\w+)\/(\w+)/;
-	    if ($StdNo) { 
-		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
-	    }
-#-------------------------------- Row of statistical table
-            &TableRow($cache,$join,$cIdx,($p_count-1),$r,$color,\%GraphDat);
-	}
-	&CloseTable($cache,$r);
-    }
-###    &Close_PrgWin();
-#666666
-#    close( OUT );
-#666666
-}
+=pod 
 
-=pod
-sub Cache_Statistics {
-    my ($cache,$color)=@_;
-    my @list = ();
-    my $Useful;
-    my $UnUseful;
-#    $r->print('<input type="hidden" name="show" value="excel" />'."\n"); 
-    my %myHeader = reverse( %Header );
-    $Pos = $myHeader{$ENV{'form.sort'}};
-    if ($Pos > 0) {$Pos++;}
-    my $p_count = 0;
-    foreach my $key( keys %CachData) { 
-	my @Temp=split(/\&/,$CachData{$key});
-	if ( $Pos == 0 ) {
-	    ($UnUseful,$Useful)=split(/\>/,$Temp[$Pos]);
-	}
-	else {
-	    $Useful = $Temp[$Pos];
-	}   
-	$list[$p_count]=$Useful.'@'.$CachData{$key};
-        $p_count++;
-    }
-
-    @list = sort MySort (@list);
-
-    my $nIndex=0;
-
-    if ( $Pos == 0 ) {
-	foreach (sort keys %mapsort) {
-	    my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	    &CreateProblemStatisticsTableHeading($cache,1,$Hid);
-	    my @lpr=split(/\&/,$pr);
-	    for (my $i=1; $i<=$#lpr; $i++) {
-		my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
-		#$r->print('<br>'.$Pre.'---'.$Post);
-		&TableRow($cache,$Post,$i,$nIndex,$color,\%GraphDat);
-		$nIndex++;
-	    }
-	    &CloseTable($cache);
-	}
-    }
-    else {
-	&CreateProblemStatisticsTableHeading($cache,0);
-	for ( my $nIndex = 0; $nIndex < $p_count; $nIndex++ ) {
-	    my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
-	    &TableRow($cache,$Post,$nIndex,$nIndex,$color,\%GraphDat);
-	} 
-	&CloseTable($cache);
+=item &statistics_html_table_data()
+
+Help function used to format the rows for HTML table output.
+
+=cut
+
+###############################################
+###############################################
+sub statistics_html_table_data {
+    my ($data,$options) = @_;
+    my $row = '';
+    foreach my $field (@Fields) {
+        next if ($options =~ /no $field->{'name'}/);
+        $row .= '<td bgcolor="'.$field->{'color'}.'"';
+        if (exists($field->{'align'})) {
+            $row .= ' align="'.$field->{'align'}.'"';
+            }
+        $row .= '>';
+        if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
+            $row .= '<a href="'.$data->{$field->{'name'}.'.link'}.'">';
+        }
+        if (exists($field->{'format'})) {
+            $row .= sprintf($field->{'format'},$data->{$field->{'name'}});
+        } else {
+            $row .= $data->{$field->{'name'}};
+        }
+        if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
+            $row.= '</a>';
+        }
+        $row .= '</td>';
     }
+    return $row;
 }
-=cut 
 
-sub TableRow {
-    my ($cache,$Str,$Idx,$RealIdx,$r,$color,$GraphDat)=@_;
-    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
-       $Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$DiscNo,$Prob)=split(/\&/,$Str);	
-#    $r->print('<br>'.$Str);
-    my $Ptr;
-    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
-        my ($ResId,$Dummy)=split(/\*/,$Prob);
-        $Ptr="\n".'<br>'.
-             "\n".'"'.($RealIdx+1).'",'.
-             "\n".'"'.$cache->{'title_'.$ResId}.$Dummy.'",'.
-             "\n".'"'.$cache->{'src_'.$ResId}.'",'.
-             "\n".'"'.$StdNo.'",'.
-             "\n".'"'.$TotalTries.'",'.
-             "\n".'"'.$MxTries.'",'.
-             "\n".'"'.$Avg.'",'.
-             "\n".'"'.$YES.'",'.
-             "\n".'"'.$Override.'",'.
-             "\n".'"'.$Wrng.'",'.
-             "\n".'"'.$DoD.'",'.
-             "\n".'"'.$SD.'",'.
-             "\n".'"'.$Sk.'",'.
-             "\n".'"'.$_D1.'",'.
-	     "\n".'"'.$_D2.'"'.
-	     "\n".'"'.$DiscNo.'"';
-
-        $r->print("\n".$Ptr);
-    } else {
-        $Ptr="\n".'<tr>'.
-             "\n".'<td>'.($RealIdx+1).'</td>'.
-          #  "\n".'<td>'.$PrOrd.$Temp.'</td>'.
-             "\n".'<td>'.$Temp.'</td>'.
-             "\n".'<td bgcolor='.$color->{"yellow"}.'> '.$StdNo.'</td>'.
-             "\n".'<td bgcolor='.$color->{"yellow"}.'>'.$TotalTries.'</td>'.
-             "\n".'<td bgcolor='.$color->{"yellow"}.'>'.$MxTries.'</td>'.
-             "\n".'<td bgcolor='.$color->{"gb"}.'>'.$Avg.'</td>'.
-             "\n".'<td bgcolor='.$color->{"gb"}.'> '.$YES.'</td>'.
-             "\n".'<td bgcolor='.$color->{"gb"}.'> '.$Override.'</td>'.
-             "\n".'<td bgcolor='.$color->{"red"}.'> '.$Wrng.'</td>'.
-             "\n".'<td bgcolor='.$color->{"red"}.'> '.$DoD.'</td>'.
-             "\n".'<td bgcolor='.$color->{"green"}.'> '.$SD.'</td>'.
-             "\n".'<td bgcolor='.$color->{"green"}.'> '.$Sk.'</td>'.
-             "\n".'<td bgcolor='.$color->{"purple"}.'> '.$_D1.'</td>'.
-	     "\n".'<td bgcolor='.$color->{"purple"}.'> '.$_D2.'</td>'.
-             "\n".'<td bgcolor='.$color->{"yellow"}.'> '.$DiscNo.'</td>';
-        $r->print("\n".$Ptr.'</tr>' );
+sub statistics_table_header {
+    my ($options) = @_;
+    my $header_row;
+    foreach my $field (@Fields) {
+        next if ($options =~ /no $field->{'name'}/);
+        $header_row .= '<th>';
+        if ($options =~ /sortable/ && 
+            exists($field->{'sortable'}) && $field->{'sortable'} eq 'yes') {
+            $header_row .= '<a href="javascript:'.
+                'document.Statistics.sortby.value='."'".$field->{'name'}."'".
+                    ';document.Statistics.submit();">';
+        }
+        $header_row .= &mt($field->{'title'});
+        if ($options =~ /sortable/) {
+            $header_row.= '</a>';
+        }
+        if ($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>';
     }
-#    $GraphDat->{$RealIdx}=$DoD.':'.$Wrng;
+    return $header_row;
 }
 
+###############################################
+###############################################
 
-# For loading the colored table for display or un-colored for print
-sub setbgcolor {
-    my $PrintTable=shift;
-    my %color;
-    if ($PrintTable){
-	$color{"gb"}="#FFFFFF";
-	$color{"red"}="#FFFFFF";
-	$color{"yellow"}="#FFFFFF";
-	$color{"green"}="#FFFFFF";
-	$color{"purple"}="#FFFFFF";
-    } else {
-	$color{"gb"}="#DDFFFF";
-	$color{"red"}="#FFDDDD";
-	$color{"yellow"}="#EEFFCC";
-	$color{"green"}="#DDFFDD";
-	$color{"purple"}="#FFDDFF";
-    }
+=pod 
 
-    return \%color;
-}
+=item &plot_statistics()
 
-sub ProblemStatisticsButtons {
-    my ($displayFormat)=@_;
+=cut
 
-    my $Ptr = '<tr><td></td><td align="left">';
-    $Ptr .= '<input type="submit" name="DoDiffGraph" ';
-    $Ptr .= 'value="DoDiff Graph" />'."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="PercentWrongGraph" ';
-    $Ptr .= 'value="%Wrong Graph" />'."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="DisplayCSVFormat" ';
-    if($displayFormat eq 'Display CSV Format') {
-        $Ptr .= 'value="Display Table Format" />'."\n";
-    } else {
-        $Ptr .= 'value="Display CSV Format" />'."\n";
+###############################################
+###############################################
+sub plot_statistics {
+    my ($r,$datafield) = @_;
+    my @Data;
+    #
+    #
+    my $sortfield = undef;
+    my $title = undef;
+    foreach my $field (@Fields) {
+        if ($datafield eq $field->{'name'} &&
+            exists($field->{'graphable'}) && $field->{'graphable'} eq 'yes') {
+            $sortfield = $field->{'name'};
+            $title = $field->{'long_title'};
+        }
     }
-    $Ptr .= '</td></tr>';
+    return if (! defined($sortfield) || $sortfield eq '');
+    #
+    my $Max = 0;
+    my $problem_num = 0;
+    foreach my $sequence (&Apache::lonstatistics::Sequences_with_Assess()) {
+        next if ($sequence->{'num_assess'}<1);
+        foreach my $resource (@{$sequence->{'contents'}}) {
+            next if ($resource->{'type'} ne 'assessment');
+            foreach my $part (@{$resource->{'parts'}}) {
+                my $problem_number++;
+                my $data = &get_statistics($sequence,$resource,$part,
+                                           $problem_num);
+                my $value = $data->{$sortfield};
+                $Max = $value if ($Max < $value);
+                push (@Data,$value);
+            }
+        }
+    }
+    #
+    # Print out plot request
+    my $yaxis = '';
+    if ($sortfield eq 'per_wrong') {
+        $yaxis = 'Percent';
+    }
+    #
+    # Determine appropriate value for $Max
+    if ($sortfield eq 'deg_of_diff') {
+        if ($Max > 0.5) {
+            $Max = 1;
+        } elsif ($Max > 0.2) {
+            $Max = 0.5;
+        } elsif ($Max > 0.1) {
+            $Max = 0.2;
+        }
+    } elsif ($sortfield eq 'per_wrong') {
+        if ($Max > 50) {
+            $Max = 100;
+        } elsif ($Max > 25) {
+            $Max = 50;
+        } elsif ($Max > 20) {
+            $Max = 25;
+        } elsif ($Max > 10) {
+            $Max = 20;
+        } elsif ($Max > 5) {
+            $Max = 10;
+        } else {
+            $Max = 5;
+        }
+    }
+    
+    $r->print("<p>".&Apache::loncommon::DrawBarGraph($title,
+                                                     'Problem Number',
+                                                     $yaxis,
+                                                     $Max,
+                                                     undef,
+                                                     \@Data)."</p>\n");
+    #
+    # Print out the data
+    $ENV{'form.sortby'} = 'Contents';
+#    &output_html_ungrouped($r);
+    return;
+}
 
-    return $Ptr;
+sub get_statistics {
+    my ($sequence,$resource,$part,$problem_num) = @_;
+    #
+    my $symb = $resource->{'symb'};
+    my $courseid = $ENV{'request.course.id'};
+    #
+    my $students = \@Apache::lonstatistics::Students;
+    if ($Apache::lonstatistics::SelectedSections[0] eq 'all') {
+        $students = undef;
+    }
+    my $data = &Apache::loncoursedata::get_problem_statistics
+                        ($students,$symb,$part,$courseid);
+    $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'});
+    #
+    return $data;
 }
 
+###############################################
+###############################################
+
+=pod 
+
+=item &ProblemStatisticsLegend()
+
+HELP  This needs to be localized, or at least generated automatically.
+
+=cut
+
+###############################################
+###############################################
 sub ProblemStatisticsLegend {
     my $Ptr = '';
     $Ptr = '<table border="0">';
     $Ptr .= '<tr><td>';
     $Ptr .= '<b>#Stdnts</b></td>';
-    $Ptr .= '<td>Total Number of Students opened the problem.';
+    $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>Total number of tries for solving the problem.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Mod</b></td>';
-    $Ptr .= '<td>Maximunm Number of Tries for solving the problem.';
+    $Ptr .= '<b>Max Tries</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 the tries. [ Tries / #Stdnts ]';
+    $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.';
@@ -704,9 +839,9 @@ sub ProblemStatisticsLegend {
     $Ptr .= '<b>#yes</b></td>';
     $Ptr .= '<td>Number of students solved the problem by override.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>%Wrng</b></td>';
-    $Ptr .= '<td>Percentage of students tried to solve the problem ';
-    $Ptr .= 'but still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]';
+    $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.  ';
@@ -724,8 +859,8 @@ sub ProblemStatisticsLegend {
     $Ptr .= '<b>Dis.F.</b></td>';
     $Ptr .= '<td>Discrimination Factor: A Standard for evaluating the ';
     $Ptr .= 'problem according to a Criterion<br>';
-    $Ptr .= '<b>[Applied Criterion in %27 Upper Students - ';
-    $Ptr .= 'Applied the same Criterion in %27 Lower Students]</b><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: ';
@@ -734,151 +869,10 @@ sub ProblemStatisticsLegend {
     $Ptr .= '<tr><td><b>Disc.</b></td>';
     $Ptr .= '<td>Number of Students had at least one discussion.';
     $Ptr .= '</td></tr></table>';
-
     return $Ptr;
 }
 
-#------- Processing upperlist and lowerlist according to each problem
-sub ProcessDiscriminant {
-    my ($List,$r) = @_;
-    my @sortedList = sort (@$List);
-    my $Count = scalar @sortedList;
-    my $Problem;
-    my @Dis;
-    my $Slvd=0;
-    my $tmp;
-    my $Sum1=0;
-    my $Sum2=0;
-    my $nIndex=0;
-    my $nStudent=0;
-    my %Proc=undef;
-    while ($nIndex<$Count) {
-#        $r->print("<br> $nIndex) $sortedList[$nIndex]");
-	($Problem,$tmp)=split(/\=/,$sortedList[$nIndex]);
-	@Dis=split(/\+/,$tmp);
-	my $Temp = $Problem;
-	do {
-	    $nIndex++;
-	    $nStudent++;
-	    $Sum1 += $Dis[0];
-	    $Sum2 += $Dis[1];
-	    ($Problem,$tmp)=split(/\=/,$sortedList[$nIndex]);
-	    @Dis=split(/\+/,$tmp);
-	} while ( $Problem eq $Temp && $nIndex < $Count );
-	$Proc{$Temp}=($Sum1/$nStudent).':'.($Sum2/$nStudent);
-#        $r->print("<br> $nIndex) $Temp --> ($nStudent) $Proc{$Temp}");
-	$Sum1=0;
-	$Sum2=0;
-	$nStudent=0;
-    }
-
-    return %Proc;
-}
-
-#------- Creating Discimination factor   
-sub Discriminant {
-    my ($discriminant,$r)=@_;
-#$Apache::lonxml::debug=1;
-#&Apache::lonhomework::showhash(%$discriminant);
-#$Apache::lonxml::debug=0;
-    my @discriminantKeys=keys(%$discriminant);
-    my $Count = scalar @discriminantKeys;
-
-    my $UpCnt = int(0.27*$Count);
-    my $low=0;
-    my $up=$Count-$UpCnt;
-    my @UpList=();
-    my @LowList=();
-
-    $Count=0;
-    foreach my $key (sort(@discriminantKeys)) { 
-	$Count++;    
-	if($low < $UpCnt || $Count > $up) {
-            $low++;
-            my $str=$discriminant->{$key};
-            foreach(split(/\&/,$str)){
-                if($_) {
-                    if($low<$UpCnt) { push(@LowList,$_); }
-                    else            { push(@UpList,$_);  }
-                }
-            }
-        }
-    }
-    my %DisUp =  &ProcessDiscriminant(\@UpList,$r);
-    my %DisLow = &ProcessDiscriminant(\@LowList,$r);
-
-    return (\%DisUp, \%DisLow);
-}   
-
 #---- END Problem Statistics Web Page ----------------------------------------
 
-#---- Problem Statistics Graph Web Page --------------------------------------
-
-# ------------------------------------------- Prepare data for Graphical chart
-
-sub BuildDiffGraph {
-    my ($r)=@_;
-
-    my $graphData = &GetGraphData('DiffGraph', $r);
-    $r->print('<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />');
-
-    return;
-}
-
-sub BuildWrongGraph {
-    my ($r)=@_;
-
-    my $graphData = &GetGraphData('WrongGraph', $r);
-    $r->print('<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />');
-
-    return;
-}
-
-
-sub GetGraphData {
-    my ($ylab,$r,%GraphDat)=@_;
-    my $Col;
-    my $data='';
-    my $count = 0;
-    my $Max = 0;
-    my $cid=$ENV{'request.course.id'};
-    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_graph.db";
-    foreach (keys %GraphDat) {delete $GraphDat{$_};}
-    if (-e "$GraphDB") {
-	if (tie(%GraphDat,'GDBM_File',"$GraphDB",&GDBM_READER,0640)) {
-	    if ( $ylab eq 'DoDiff Graph' ) {
-		$ylab = 'Degree-of-Difficulty';
-		$Col = 0;
-	    }
-	    else {
-		$ylab = 'Wrong-Percentage';
-		$Col = 1;
-	    }
-	    foreach (sort NumericSort keys %GraphDat) { 
-		my @Temp=split(/\:/,$GraphDat{$_});
-                my $inf = $Temp[$Col]; 
-		if ( $Max < $inf ) {$Max = $inf;}
-		$data .= $inf.',';
-		$count++;
-	    }
-	    if ( $Max > 1 ) { 
-		$Max += (10 - $Max % 10);
-		$Max = int($Max);
-	    }
-	    else { $Max = 1; }
-            untie(%GraphDat);
-	    my $Course = $ENV{'course.'.$cid.'.description'};
-	    $Course =~ s/\ /"_"/eg;
-	    my $GData=$Course.'&'.'Problems'.'&'.$ylab.'&'.
-		      $Max.'&'.$count.'&'.$data;
-	}
-	else {
-	    $r->print("Unable to tie hash to db file");
-	}
-    }
-}
-
-
 1;
 __END__