--- loncom/interface/statistics/lonproblemstatistics.pm	2002/07/24 14:52:32	1.1
+++ loncom/interface/statistics/lonproblemstatistics.pm	2002/08/14 13:13:37	1.24
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # (Publication Handler
 #
-# $Id: lonproblemstatistics.pm,v 1.1 2002/07/24 14:52:32 stredwic Exp $
+# $Id: lonproblemstatistics.pm,v 1.24 2002/08/14 13:13:37 stredwic Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,7 @@
 # 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  Behrouz Minaei
+# 5/12,5/14,5/15,5/19,5/26,7/16,7/25,7/29,8/5  Behrouz Minaei
 #
 ###
 
@@ -43,921 +43,340 @@ use Apache::lonhtmlcommon;
 use Apache::loncoursedata;
 use GDBM_File;
 
-my $r;
-my %DoDiff;
-my %Discuss;
-my %mapsort;
-my %hash;
-my %CachData;
-my %color;
-my %GraphDat;
+my $jr;
 
 sub BuildProblemStatisticsPage {
-    my ($cacheDB, $students, $courseID, $c, $jr)=@_;
-
-    $r = $jr;
+    my ($cacheDB, $students, $courseID, $c, $r)=@_;
     my %cache;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
+
+    $jr = $r;
+
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+        $r->print('Unable to tie database.');
+        return;
     }
 
     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');
+    $Ptr .= &Apache::lonhtmlcommon::MapOptions(\%cache, 'ProblemStatistics',
+                                               'Statistics');
     $Ptr .= '</td></tr>'."\n";
-    $Ptr .= &AscendOrderOptions($cache{'Ascend'});
-    $Ptr .= &ProblemStatisticsButtons($cache{'DisplayFormat'});
-   $Ptr .= '</table>';
-
-    $Ptr .= &ProblemStatisticsLegend();
+    $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'}, 
+                                      $cache{'DisplayLegend'});
+    $Ptr .= '</table>';
+    if($cache{'DisplayLegend'} eq 'Show Legend') {
+        $Ptr .= &ProblemStatisticsLegend();
+    }
+    $r->print($Ptr);
+    $r->rflush();
 
-    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, $_);
+    my @Header = ("Homework Sets Order","#Stdnts","Tries","Mod",
+                  "Mean","#YES","#yes","%Wrng","DoDiff",
+                  "S.D.","Skew.","D.F.1st","D.F.2nd","Disc.");
+    my $color=&setbgcolor(0);
+
+#    my %Discuss=&Apache::loncoursedata::LoadDiscussion($courseID);
+#    my ($upper, $lower) = &Discriminant(\%discriminant,$r);
+    if(!defined($cache{'StatisticsCached'})) {
+        if(defined($cache{'StatisticsCached'})) {
             untie(%cache);
+            unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
+                $r->print('Unable to tie database.');
+                return;
+            }
+            my @statkeys = split(':::', $cache{'StatisticsKeys'});
+            delete $cache{'StatisticsKeys'};
+            delete $cache{'StatisticsCached'};
+            foreach(@statkeys) {
+                delete $cache{$_};
+            }
+        }
+        untie(%cache);
+        &Apache::loncoursedata::DownloadStudentCourseDataSeparate($students,
+                                                                  'true',
+                                                                  $cacheDB,
+                                                                  'true', 
+                                                                  'true',
+                                                                  $courseID,
+                                                                  $r, $c);
+        if($c->aborted()) { return; }
+
+        unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+            $r->print('Unable to tie database.');
+            return;
+        }
+        my ($problemData) = &ExtractStudentData(\%cache, $students);
+        &CalculateStatistics($problemData, \%cache);
+        untie(%cache);
+
+        unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
+            $r->print('Unable to tie database.');
+            return;
+        }
+        foreach(keys(%$problemData)) {
+            $cache{$_} = $problemData->{$_};
+        }
+        $cache{'StatisticsKeys'} = join(':::', keys(%$problemData));
+        $cache{'StatisticsCached'} = 'true';
+        untie(%cache);
+
+        unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+            $r->print('Unable to tie database.');
+            return;
         }
     }
-    if($c->aborted()) { return $Ptr; }
-
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
-    }
-    my $discriminantFactor;
-    my @list=();
-    foreach (@$students) {
-        $discriminantFactor = &ExtractStudentData(\%cache, $_, \@list);
-    }
-    return $Ptr;
-    my ($upper, $lower) = &Discriminant($discriminantFactor);
-    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.");
-    &Apache::loncoursedata::LoadDiscussion($courseID, $courseID, \%Discuss);
-    &BuildStatisticsTable(\%cache, $discriminantFactor, \@list, \%Header, 
-                           $students);
-
+    my $orderedProblems = &SortProblems(\%cache, 
+                                        $cache{'ProblemStatisticsSort'},
+                                        $cache{'ProblemStatisticsAscend'});
+    &BuildStatisticsTable(\%cache, $cache{'DisplayFormat'}, $orderedProblems, 
+                          \@Header, $r, $color);
     untie(%cache);
 
-    return $Ptr;
+    return;
 }
 
-sub BuildDiffGraph {
-    my ($courseID)=@_;
-
-    my $graphData = &GetGraphData('DiffGraph', $courseID);
-    return '<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />';
-}
-
-sub BuildWrongGraph {
-    my ($courseID)=@_;
-
-    my $graphData = &GetGraphData('WrongGraph', $courseID);
-    return '<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />';
-}
-
-#---- Activity log -------------------------------------------------------
-
-sub LoadDoDiffFile {
-    my $file="/home/minaeibi/183d.txt";
-    open(FILEID, "<$file");
-    my $line=<FILEID>;
-    my %DoDiff=();
-    my @Act=split('&',$line);
-    
-#    $r->print('<br>'.$#Act);
-    for(my $n=0;$n<=$#Act;$n++){
-       my ($res,$Degree)=split('@',$Act[$n]);
-      $DoDiff{$res}=$Degree;
-    }
-
-    return \%DoDiff;
-}
-
-sub LoadClassFile {
-    my $file="/home/minaeibi/class.txt";
-    open(FILEID, "<$file");
-    my $line;
-    my %Grade=();
-    while ($line=<FILEID>) {
-        my ($id,$ex1,$ex2,$ex3,$ex4,$hw,$final,$grade)=split(' ',$line);
-        $Grade{$id}=$grade;
-    }
-    return \%Grade;
-}
+sub BuildGraphicChart {
+    my ($graph,$cacheDB,$courseDescription,$r)=@_;
+    my %cache;
+    my $max = 0;
 
-#------- Classification  
-sub Classify {
-    my ($DiscFac, $students)=@_;
-    my ($fileGrade) = &LoadClassFile();
-    my $Count=0;
-    my @List=();
-    my @LS=();
-    my @LF=();
-    my @LM=();
-    my $cf=0;
-    my $cs=0;
-    my $cm=0;
-    foreach (keys(%$DiscFac)){  
-	my @l=split(/\:/,$_);
-	if (!($students->{$l[1]})) {next;}
-	my $Grade=$fileGrade->{$students->{$l[1]}};
-	if( $Grade > 3 ) {
-	    $cs++;
-	    push(@LS,("$l[6],$l[5],$l[4],$l[7],$l[8],$l[9],Successful"));
-	} elsif ( $Grade > 2 ) {
-	    $cm++;
-	    push(@LM,("$l[6],$l[5],$l[4],$l[7],$l[8],$l[9],Average"));
-	} else {
-	    $cf++;
-	    push(@LF,("$l[6],$l[5],$l[4],$l[7],$l[8],$l[9],Failed"));
-	}
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+        return '<html><body>Unable to tie database.</body></html>';
     }
-    my $Str = '';
-    for(my $n=0;$n<$cs;$n++){$Str .= '<br>'.$LS[$n];}
-    for(my $n=0;$n<$cm;$n++){$Str .= '<br>'.$LM[$n];}  
-    for(my $n=0;$n<$cf;$n++){$Str .= '<br>'.$LF[$n];}
-
-    return $Str;
-} 
-
-sub ProcAct {
-    # return;
-    my ($Act,$Submit)=@_;
-    my @Act=split(/\@/,$Act);
-    @Act = sort(@Act);
-
-    ##$r->print('<br>'.$#Act);
-    ##for(my $n=0;$n<=$#Act;$n++){
-##	$r->print('<br>n='.$n.')'.$Act[$n]);
-##    }
-
-#    my $Beg=$Act[0];
-    my $Dif=$Submit-$Act[0];
-    $Dif = ($Dif>0) ? ($Dif/3600) : 0; 
-
-#    $r->print('<br>Access Number = '.$#Act.'<br>Submit Time='.$Submit.'<br>First Access='.$Act[0].'<br>Last Access='.$Act[$#Act].'<br> Submit - First = <b>'.$Dif.'</b>');
-
-
-#time spent for solving the problem           
-#    $r->print('<br>Def'.($Act[$#Act-1]-$Act[0]));
-
-    return $Dif;
-}
-
-sub LoadActivityLog {
-#    my $CacheDB = "/home/minaeibi/act183.log.cache";
-    my $CacheDB = "/home/httpd/perl/tmp/act183.log.cache";
-
-    my %Activity;
-    if (-e "$CacheDB") {
-	if (tie(%Activity,'GDBM_File',"$CacheDB",&GDBM_READER,0640)) {
-	    return;
-        }
-        else {
-#	    $r->print("Unable to tie log Cache hash to db file");
+   
+    my @problems = split(':::', $cache{'problemList'});
+    my @values = ();
+    foreach (@problems) {
+        my $data = 0;
+        if($graph eq 'DoDiffGraph') {
+            $data = sprintf("%.2f", $cache{$_.':degreeOfDifficulty'}),
+        } else {
+            $data = sprintf("%.1f", $cache{$_.':percentWrong'}),
         }
-    }
-    else {
-	if (tie(%Activity,'GDBM_File',$CacheDB,&GDBM_WRCREAT,0640)) {
-	    foreach (keys %Activity) {delete $Activity{$_};}
-	    &Build_log(\%Activity); 
-	}
-        else {
-#	    $r->print("Unable to tie log Build hash to db file");
+        if($max < $data) {
+            $max = $data;
         }
+        push(@values, $data);
     }
-    return \%Activity;
-}
-
-sub Build_log {
-    my ($Activity)=@_;
-    my $file="/home/minaeibi/act183.log";
-    open(FILEID, "<$file");
-    my $line;
-    my $count=0;
-    while ($line=<FILEID>) {
-	my ($time,$machine,$what)=split(':',$line);
-	$what=&Apache::lonnet::unescape($what);
-	my @accesses=split('&',$what);
-	           
-	foreach my $access (@accesses) {
-
-	    $count++;
-
-	    my ($date,$resource,$who,$domain,$post,@posts)=split(':',$access);
-	    if (!$resource) { next; }
-	    my $res=&Apache::lonnet::unescape($resource);
-	    if (($res =~ /\.problem/)) {
-		$Activity->{$who.':'.$res}.=$date.'@';
-                #$r->print('<br>'.$time.':'.$who.'---'.$res);
-		&Update_PrgInit($count);
+    untie(%cache);
 
-	    }
-	}
+    my $sendValues = join(',', @values);
+#    my $sendCount = $#values;
+    my $sendCount = scalar(@values);
+
+    my $title = '';
+    if($graph eq 'DoDiffGraph') {
+	$title = 'Degree-of-Difficulty';
+    } else {
+	$title = 'Wrong-Percentage';
     }
+    my @GData = ($courseDescription, 'Problems', $title, $max, $sendCount, 
+                 $sendValues);
 
-# my $c=1;
-# foreach (sort keys %Activity) {
-#     $r->print('<br>'.$c.')'.$_.' ... '.$Activity{$_});
-#     $c++;
-# }
+    $r->print('</form>'."\n");
+    $r->print('<IMG src="/cgi-bin/graph.gif?'.(join('&', @GData)).'" border="1" />');
+    $r->print('<form>'."\n");
 
+    return;
 }
 
-sub Activity {
-#    $rid=~/(\d+)\.(\d+)/;
-#    my $MapId=$1;
-#    my $PrbId=$2;
-#    my $MapOrg = $hash{'map_id_'.$MapId};
-#    my $Map = &Apache::lonnet::declutter($MapOrg);
-#    my $URI = $hash{'src_'.$rid};
-#    my $Symb = $Map.'___'.$PrbId.'___'.&Apache::lonnet::declutter($URI);
-    my $file="/home/minaeibi/activity.log";
-    my $userid='adamsde1';
-    $r->print("<br>Using $file");
-    $r->rflush();
-    open(FILEID, "<$file");
-    my $line;
-    my @allaccess;
-    my $Count=0;
-    while ($line=<FILEID>) {
-	my ($time,$machine,$what)=split(':',$line);
-	$what=&Apache::lonnet::unescape($what);
-	my @accesses=split('&',$what);
-	foreach my $access (@accesses) {
-	    my ($date,$resource,$who,$domain,$post,@posts)=split(':',$access);
-	    #if ($who ne $userid) { next; }
-	    if (!$resource) { next; }
-	    my $res=&Apache::lonnet::unescape($resource);
-	    if (($res =~ /\.(sequence|problem|htm|html|page)/)) {
-	    	$Count++;
-		$r->print("<br>$Count) ".localtime($date).": $who --> $res");
-#	        if ($post) { 
-#		    $Count++;
-#		    $r->print("<br><b>$Count) Sent data ".join(':',
-#                              &Apache::lonnet::unescape(@posts)).'</b>');
-#		}
-		$r->rflush();
-	    }
-	    #push (@allaccess,unescape($access));
-	    #print $machine;
-	}
-    }
-#    @allaccess=sort(@allaccess);
-#    $Count=0;
-#    foreach my $access (@allaccess) {
-#	my ($date,$resource,$who,$domain,$post,@posts)=split(':',$access);
-#	$Count++;
-#	$r->print("<br>$Count) $date: $who --> $resource");
-#	$r->rflush();
-#	if ($post) { 
-#	    $r->print("<br><b>Sent data ".join(':',unescape(@posts)).'</b>');
-#	}
-#    }
-}
-
-#---- END Activity log ---------------------------------------------------
-
 #---- Problem Statistics Web Page ---------------------------------------
 
-#------- Processing upperlist and lowerlist according to each problem
-sub ProcessDiscriminant {
-    my ($List) = @_;
-    my @sortedList = sort (@$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<$Count) {
-	($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).':'.$nStudent;
-	$Proc{$Temp}=($Sum1/$nStudent).':'.($Sum2/$nStudent);
-#       $r->print("$nIndex) $Temp --> ($nStudent) $Proc{$Temp} <br>");
-	$Sum1=0;
-	$Sum2=0;
-	$nStudent=0;
-    }
-
-    return %Proc;
-}
-
-#------- Creating Discimination factor   
-sub Discriminant {
-    my ($discriminantFactor)=@_;
-    my @discriminantKeys=keys(%$discriminantFactor);
-    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 $str=$discriminantFactor->{$key};
-            foreach(split(/\:/,$str)){
-                if($_) {
-                    if($low<$UpCnt) { push(@LowList,$_); }
-                    else            { push(@UpList,$_);  }
-                }
-            }
-        }
-    }
-    my %DisUp =  &ProcessDiscriminant(\@UpList);
-    my %DisLow = &ProcessDiscriminant(\@LowList);
-
-    return (\%DisUp, \%DisLow);
-}
-
-   
-sub NumericSort {          
-    $a <=> $b;
-}
-
-
 sub CreateProblemStatisticsTableHeading {
-    my ($displayFormat,$sequenceSource,$sequenceTitle,$headings)=@_;
-    if($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";
-    }
-    $Result .= "\n".'</tr>'."\n";    
-    $r->print($Result);
-    $r->rflush();
-}
-
-sub CloseTable {
-    my ($cache)=@_;
-    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
-	return;
-    }    
-    $r->print("\n".'</table>'."\n");
-    $r->rflush();
-}
-
-
- 
-# ------ Dump the Student's DB file and handling the data for statistics table 
-sub ExtractStudentData {
-    my ($cache,$name,$list)=@_;
-    my %discriminantFactor;
-
-    my $totalTries = 0;
-    my $totalAwarded = 0;
-    my $tempProblemOrder=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;
-
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-        if($cache->{'ProblemStatisticsMap'} ne 'All Maps'  &&
-           $cache->{'ProblemStatisticsMap'} ne $cache->{$sequence.':title'}) {
-            next;
-        }
-
-        my $Dis = '';
-        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
-            my $problem = $cache->{$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;
-            # 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'})) {
-                $partData{$part.':tries'}=0;
-                $partData{$part.':code'}='-';
-            }
-
-            # 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;
-                    }
-
-                    my $tries=0;
-                    my $time=0;
-                    my $awarded=0;
-		    $Discussed=0;
-                    my $code='U';
-
-                    $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 += $tries;
+    my ($headings,$r)=@_;
 
-                    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'}--;
-                    }
-                }
-            }
-
-            # Loop through all the parts for the current problem in the 
-            # correct order and prepare the output
-            foreach (split(/\:/,$cache->{$sequence.':'.$problemID.
-                                         ':parts'})) {
-                my $Yes = 0;
-                if($partData{$_.':code'} eq 'C' || 
-                   $partData{$_.':code'} eq 'O') {
-                    $Yes=1;
-                }
-                #my $ptr = "$hash{'title_'.$ResId}";
-                my $ptr = $tempProblemOrder.'&'.$problemID;
-
-                if($_ > 1) {
-                    $ptr .= "*(part $_)";
-                    $Dis .= '&';
-                }
-
-		my ($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 = $Fac;
-                }
-
-                if ($Discuss{"$name:$problem"}) {
-		    $TotDiscuss++;
-                    $Discussed=1;
-                }
-                my $time = $cache->{"$name:$LatestVersion:$problem:timestamp"};
-                $Dis .= $tempProblemOrder.'='.$DisF.'+'.$Yes;
-                $ptr .= '&'.$partData{$_.'.Tries'}.
-                        '&'.$partData{$_.'.Wrongs'}.
-                        '&'.$partData{$_.'.Code'};
-                push (@$list, $ptr."&$Discussed");
-
-####		if ($DoDiff>0.85) {
-
-                $TimeTot += $time;
-
-                if ($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++;
-
-                $tempProblemOrder++;
-            }
-        }
-	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 );
-	   # $DiscFac{$DisFactor}=$Dis;
-	    $pstr=$DisFactor.':'.$name.':'.$ProbTot.':'.$TotalOpend.':'.
-                  $totalTries.':'.$ProbSolved.':'.$TotFirst.':'.
-                  $TS_yes.':'.$TS.':'.$TotDiscuss;
-	    $discriminantFactor{$pstr}=$Dis;
-	}
+    my $Str='';
+    $Str .= '<tr>'."\n";
+    $Str .= '<th bgcolor="#ffffe6">P#</th>'."\n";
+    foreach(@$headings) {
+	$Str .= '<th bgcolor="#ffffe6">'.'<a href="/adm/statistics?reportSelected=';
+        $Str .= &Apache::lonnet::escape('Problem Statistics');
+        $Str .= '&ProblemStatisticsSort=';
+        $Str .= &Apache::lonnet::escape($_).'">'.$_.'</a>&nbsp</th>'."\n";
     }
+    $Str .= "\n".'</tr>'."\n";    
 
-    return (\%discriminantFactor);
-}
-
-
-=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; }
-    }
+    return $Str;
 }
-=cut
 
 sub BuildStatisticsTable {
-    my ($cache,$discriminantFactor,$list,$headings,$students)=@_;
+    my ($cache,$displayFormat,$orderedProblems,$headings,$r,$color)=@_;
 
 #6666666
 #    my $file="/home/httpd/perl/tmp/183d.txt";
 #    open(OUT, ">$file");
 #6666666
-    &Create_PrgWin();
+##     &Apache::lonstatistics::Create_PrgWin($r);
 ##777777
 ##    my (%Activity) = &LoadActivityLog();
 ##    $r->print('<script>popwin.document.popremain.remaining.value="'.
 ##              'Loading Discussion...";</script>');
 ##    my ($doDiffFile) = &LoadDoDiffFile();
 
-    my $p_count = 0;
-    my $nIndex = 0;
-    my $dummy;
-    my $p_val;
-    my $ResId;
-    my $NoElements = scalar @$list;
-
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-        if($cache->{'ProblemStatisticsMap'} ne 'All Maps'  &&
-           $cache->{'ProblemStatisticsMap'} ne $cache->{$sequence.':title'}) {
-            next;
-        }
-
-	&CreateProblemStatisticsTableHeading($cache->{'DisplayFormat'},
-                                             $cache->{$sequence.':source'}, 
-                                             $cache->{$sequence.':title'},
-                                             $headings);
-
 ##777777
 ##    $Str .= &Classify($discriminantFactor, $students);
 
+     if($displayFormat ne 'Display CSV Format') {
+        $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+        $r->print('<table border="0" cellpadding="3">'."\n");
+        $r->print(&CreateProblemStatisticsTableHeading($headings, $r));
+    } else {
+        $r->print('<br>');
+    }
 
-	my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	my @lpr=split(/\&/,$pr);
-	for (my $i=1; $i<=$#lpr; $i++) {
-	    my %storestats=();
-	    my ($PrOrd,$Prob,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,$list->[$nIndex]);
-	    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 ( $PrOrd == $lpr[$i] ) 
-	    {
-		$nIndex++;
-		$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 'U' ) { $StdNo--; }
-		($PrOrd,$Prob,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,$list->[$nIndex]);
-	    }	
-
-	    $p_count++;
-	    my $Dummy;
-	    ($ResId,$Dummy)=split(/\*/,$Temp);
-
-	    $Temp = '<a href="'.$hash{'src_'.$ResId}.
-                '" target="_blank">'.$hash{'title_'.$ResId}.$Dummy.'</a>';
-
-	    my $res = &Apache::lonnet::declutter($hash{'src_'.$ResId});
-	    my $urlres=$res;
-
-	    $ResId=~/(\d+)\.(\d+)/;
-	    my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$1} );
-	    $urlres=$Map;
- 
-	    $res = '<a href="'.$hash{'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;
+    my $count = 1;
+    foreach(@$orderedProblems) {
+        my ($sequence,$problem,$part)=split(':', $_);
+        if($cache->{'ProblemStatisticsMaps'} ne 'All Maps'  &&
+           $cache->{'ProblemStatisticsMaps'} ne $cache->{$sequence.':title'}) {
+            next;
+        }
 
-#-------------------------------- 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,$Up2)=split(/\:/,':');#jason$DisUp->{$lpr[$i]});
-	    my ($Lw1,$Lw2)=split(/\:/,':');#jason$DisLow->{$lpr[$i]});
-	    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 = $lpr[$i].'&'.$Temp.'&'.$StdNo.'&'.
-                       $TotalTries.'&'.$MxTries.'&'.$Avg.'&'.
-                       $YES.'&'.$Override.'&'.$Wrng.'&'.$DoD.'&'.
-		       $SD.'&'.$Sk.'&'.$_D1.'&'.$_D2.'&'.
-                       $DiscNo.'&'.$Prob;
-	    $CachData{($p_count-1)}=$join;
+        my $ref = '<a href="'.$cache->{$problem.':source'}.
+                  '" target="_blank">'.$cache->{$problem.':title'}.'</a>';
+#        my $ref = $cache->{$problem.':title'};
+        my $title = $cache->{$problem.':title'};
+        my $source = 'source';
+        my $tableData = join('&', $ref, $title, $source,
+                       $cache->{$_.':studentCount'},
+                       $cache->{$_.':totalTries'},
+                       $cache->{$_.':maxTries'},
+                       sprintf("%.2f", $cache->{$_.':mean'}),
+                       $cache->{$_.':correct'},
+                       $cache->{$_.':correctByOverride'},
+                       sprintf("%.1f", $cache->{$_.':percentWrong'}),
+                       sprintf("%.2f", $cache->{$_.':degreeOfDifficulty'}),
+                       sprintf("%.1f", $cache->{$_.':standardDeviation'}),
+                       sprintf("%.1f", $cache->{$_.':skewness'}),
+                       sprintf("%.2f", $cache->{$_.':discriminationFactor1'}),
+                       sprintf("%.2f", $cache->{$_.':discriminationFactor2'}),
+                       0); # 0 is for discussion, need to figure out
 
 #6666666
 #	    $r->print('<br>'.$out.'&'.$DoD);
 #            print (OUT $out.'@'.$DoD.'&');
 #6666666
 
-	    $urlres=~/^(\w+)\/(\w+)/;
-	    if ($StdNo) { 
-		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
-	    }
+#check with Gerd
+#        $urlres=~/^(\w+)\/(\w+)/;
+#        if ($StdNo) {
+#            &Apache::lonnet::put('nohist_resevaldata',\%storestats,
+#                                 $1,$2);
+#        }
 #-------------------------------- Row of statistical table
-            &TableRow($cache,$join,$i,($p_count-1));
-	}
-	&CloseTable($cache);
+        &TableRow($displayFormat,$tableData,$count,$r,$color);
+        $count++;
     }
-    &Close_PrgWin();
-#666666
+    if($cache->{'DisplayFormat'} ne 'Display CSV Format') {
+        $r->print('</table>'."\n");
+    }
+    $r->print('</td></tr></table>');
+#6666666
 #    close( OUT );
 #666666
+    return;
 }
 
-=pod
-sub Cache_Statistics {
-    my ($cache)=@_;
-    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);
-		$nIndex++;
-	    }
-	    &CloseTable($cache);
-	}
-    }
-    else {
-	&CreateProblemStatisticsTableHeading($cache,0);
-	for ( my $nIndex = 0; $nIndex < $p_count; $nIndex++ ) {
-	    my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
-	    &TableRow($cache,$Post,$nIndex,$nIndex);
-	} 
-	&CloseTable($cache);
-    }
-}
-=cut 
-
 sub TableRow {
-    my ($Str,$Idx,$RealIdx)=@_;
-    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
+    my ($displayFormat,$Str,$RealIdx,$r,$color)=@_;
+    my($ref,$title,$source,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
        $Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$DiscNo,$Prob)=split(/\&/,$Str);	
-    if ($ENV{'form.showcsv'}) {
-        my ($ResId,$Dummy)=split(/\*/,$Prob);
-        my $Ptr =  "\n".'<br>'.
-               "\n".'"'.($RealIdx+1).'",'.
-               "\n".'"'.$hash{'title_'.$ResId}.$Dummy.'",'.
-               "\n".'"'.$hash{'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.'"';
+    my $Ptr;
+    if($displayFormat eq 'Display CSV Format') {
+        $Ptr="\n".'<br>'.
+             "\n".'"'.$RealIdx.'",'.
+             "\n".'"'.$title.'",'.
+             "\n".'"'.$source.'",'.
+             "\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{
-        my $Ptr =  "\n".'<tr>'.
-               "\n".'<td>'.($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>';
+    } else {
+        $Ptr="\n".'<tr>'.
+             "\n".'<td bgcolor="#ffffe6">'.$RealIdx.'</td>'.
+             "\n".'<td bgcolor="#ffffe6">'.$ref.'</td>'.
+             "\n".'<td bgcolor='.$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>' );
     }
-    $GraphDat{$RealIdx}=$DoD.':'.$Wrng;
-}
-
-sub StatusOptions {
-    my ($cache)=@_;
-
-    my $Status = $cache->{'Status'};
-    my $OpSel1 = '';
-    my $OpSel2 = '';
-    my $OpSel3 = '';
-
-    if($Status eq 'Any')         { $OpSel3 = ' selected'; }
-    elsif($Status eq 'Expired' ) { $OpSel2 = ' selected'; }
-    else                         { $OpSel1 = ' selected'; }
 
-    my $Ptr = '';
-    $Ptr .= '<tr><td align="right"><b>Student Status:</b></td>'."\n";
-    $Ptr .= '<td align="left"><select name="Status">';
-    $Ptr .= '<option'.$OpSel1.'>Active</option>'."\n";
-    $Ptr .= '<option'.$OpSel2.'>Expired</option>'."\n";
-    $Ptr .= '<option'.$OpSel3.'>Any</option>'."\n";
-    $Ptr .= '</select></td></tr>'."\n";
-
-    return $Ptr;
+    return;
 }
 
-sub AscendOrderOptions {
-    my ($order)=@_;
-
-    my $OpSel1 = '';
-    my $OpSel2 = '';
-
-    if($order eq 'Ascending') {
-        $OpSel1 = ' selected';
+# 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 {
-        $OpSel2 = ' selected';
+	$color{"gb"}="#DDFFFF";
+	$color{"red"}="#FFDDDD";
+	$color{"yellow"}="#EEFFCC";
+	$color{"green"}="#DDFFDD";
+	$color{"purple"}="#FFDDFF";
     }
 
-    my $Ptr = '';
-    $Ptr .= '<tr><td align="right"><b>Sorting Type:</b></td>'."\n";
-    $Ptr .= '<td align="left"><select name="Ascend">'."\n";
-    $Ptr .= '<option'.$OpSel1.'>Ascending</option>'."\n".
-	    '<option'.$OpSel2.'>Descending</option>'."\n";
-    $Ptr .= '</select></td></tr>'."\n";
-
-    return $Ptr;
+    return \%color;
 }
 
 sub ProblemStatisticsButtons {
-    my ($displayFormat)=@_;
+    my ($displayFormat, $displayLegend)=@_;
 
     my $Ptr = '<tr><td></td><td align="left">';
-    $Ptr .= '<input type=submit name="ProblemStatisticsRecalculate" ';
-    $Ptr .= 'value="Recalculate Statistics"/>'."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
     $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 .= '</td></tr><tr><td></td><td>'."\n";
+    $Ptr .= '<input type="submit" name="DisplayLegend" ';
+    if($displayLegend eq 'Show Legend') {
+        $Ptr .= 'value="Hide Legend" />'."\n";
+    } else {
+        $Ptr .= 'value="Show Legend" />'."\n";
+    }
     $Ptr .= '&nbsp;&nbsp;&nbsp;';
     $Ptr .= '<input type="submit" name="DisplayCSVFormat" ';
     if($displayFormat eq 'Display CSV Format') {
-        $Ptr .= 'value="Display CSV Format" />'."\n";
-    } else {
         $Ptr .= 'value="Display Table Format" />'."\n";
+    } else {
+        $Ptr .= 'value="Display CSV Format" />'."\n";
     }
     $Ptr .= '</td></tr>';
 
@@ -968,46 +387,42 @@ 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 .= '<b>#Stdnts</b></td>';
+    $Ptr .= '<td>Total number of students attempted the problem.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Tries</b>:</td>';
-    $Ptr .= '<td>Total Number of Tries for solving the problem.';
+    $Ptr .= '<b>Tries</b></td>';
+    $Ptr .= '<td>Total number of tries for solving the problem.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Mod</b>:</td>';
-    $Ptr .= '<td>Maximunm Number of Tries for solving the problem.';
+    $Ptr .= '<b>Mod</b></td>';
+    $Ptr .= '<td>Largest number of tries for solving the problem by a student.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Mean</b>:</td>';
-    $Ptr .= '<td>Average Number of the tries. [ Tries / #Stdnts ]';
+    $Ptr .= '<b>Mean</b></td>';
+    $Ptr .= '<td>Average number of tries. [ Tries / #Stdnts ]';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>#YES</b>:</td>';
+    $Ptr .= '<b>#YES</b></td>';
     $Ptr .= '<td>Number of students solved the problem correctly.';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>#yes</b>:</td>';
+    $Ptr .= '<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>';
-#    Kashy formula
-#    '<b>  DoDiff </b>: Degree of Difficulty of the problem.<br>'.
-#    '[ Tries/(#YES+#yes+0.1) ]<br>'.
-    #Gerd formula
-    $Ptr .= '<b>DoDiff</b>:</td>';
+    $Ptr .= '<b>DoDiff</b></td>';
     $Ptr .= '<td>Degree of Difficulty of the problem.  ';
     $Ptr .= '[ 1 - ((#YES+#yes) / Tries) ]';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>S.D.</b>:</td>';
+    $Ptr .= '<b>S.D.</b></td>';
     $Ptr .= '<td>Standard Deviation of the tries.  ';
     $Ptr .= '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1) ';
     $Ptr .= 'where Xi denotes every student\'s tries ]';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Skew.</b>:</td>';
+    $Ptr .= '<b>Skew.</b></td>';
     $Ptr .= '<td>Skewness of the students tries.';
     $Ptr .= '[(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]';
     $Ptr .= '</td></tr><tr><td>';
-    $Ptr .= '<b>Dis.F.</b>:</td>';
+    $Ptr .= '<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 - ';
@@ -1024,53 +439,247 @@ sub ProblemStatisticsLegend {
     return $Ptr;
 }
 
-#---- END Problem Statistics Web Page ----------------------------------------
+#------- Processing upperlist and lowerlist according to each problem
+
+sub ExtractStudentData {
+    my ($cache, $students)=@_;
+
+#$Apache::lonxml::debug=1;
+#&Apache::lonhomework::showhash(%$cache);
+#$Apache::lonxml::debug=0;
+
+    my @problemList=();
+    my %problemData;
+    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
+        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
+            foreach my $part (split(/\:/,$cache->{$sequence.':'.
+                                                  $problemID.
+                                                  ':parts'})) {
+                my $id = $sequence.':'.$problemID.':'.$part;
+                push(@problemList, $id);
+                my $totalTries = 0;
+                my $totalAwarded = 0;
+                my $correct = 0;
+                my $correctByOverride = 0;
+                my $studentCount = 0;
+                my $maxTries = 0;
+                my $totalFirst = 0;
+                my @studentTries=();
+                foreach(@$students) {
+                    my $code = $cache->{"$_:$problemID:$part:code"};
+
+                    if(defined($cache->{$_.':error'}) || $code eq ' ' ||
+                       $cache->{"$_:$problemID:NoVersion"} eq 'true') {
+                        next;
+                    }
 
-#---- Problem Statistics Graph Web Page --------------------------------------
+                    $studentCount++;
+                    my $tries =  $cache->{"$_:$problemID:$part:tries"};
+                    if($maxTries < $tries) {
+                        $maxTries = $tries;
+                    }
+                    $totalTries += $tries;
+                    push(@studentTries, $tries);
 
-# ------------------------------------------- Prepare data for Graphical chart
+                    my $awarded = $cache->{"$_:$problemID:$part:awarded"};
+                    $totalAwarded += $awarded;
 
-sub GetGraphData {
-    my $ylab = shift;
-    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 {
-	    $r->print("Unable to tie hash to db file");
-	}
+                    if($code eq '*') {
+                        $correct++;
+                        if($tries == 1) {
+                            $totalFirst++;
+                        }
+                    } elsif($code eq '+') {
+                        $correctByOverride++;
+                    }
+                }
+
+                $problemData{$id.':sequenceTitle'} = 
+                    $cache->{$sequence.':title'};
+                $problemData{$id.':studentCount'} = $studentCount;
+                $problemData{$id.':totalTries'} = $totalTries;
+                $problemData{$id.':studentTries'} = \@studentTries;
+                $problemData{$id.':totalAwarded'} = $totalAwarded;
+                $problemData{$id.':correct'} = $correct;
+                $problemData{$id.':correctByOverride'} = $correctByOverride;
+                $problemData{$id.':wrong'} = $studentCount - 
+                                             ($correct + $correctByOverride);
+                $problemData{$id.':maxTries'} = $maxTries;
+                $problemData{$id.':totalFirst'} = $totalFirst;
+            }
+        }
     }
+
+    my @upperStudents1=();
+    my @lowerStudents1=();
+    my @upperStudents2=();
+    my @lowerStudents2=();
+    my $upperCount = int(0.27*scalar(@$students));
+    # Discriminant Factor criterion 1
+    my $sortedStudents = &SortDivideByTries($students,$cache,':totalAwarded');
+
+    for(my $i=0; $i<$upperCount; $i++) {
+        push(@lowerStudents1, $sortedStudents->[$i]);
+        push(@upperStudents1, $sortedStudents->[(scalar(@$students)-$i-1)]);
+    }
+
+    $problemData{'studentsUpperListCriterion1'}=join(':::', @upperStudents1);
+    $problemData{'studentsLowerListCriterion1'}=join(':::', @lowerStudents1);
+
+    # Discriminant Factor criterion 2
+    $sortedStudents = &SortDivideByTries($students, $cache, ':totalSolved');
+
+    for(my $i=0; $i<$upperCount; $i++) {
+        push(@lowerStudents2, $sortedStudents->[$i]);
+        push(@upperStudents2, $sortedStudents->[(scalar(@$students)-$i-1)]);
+    }
+    $problemData{'studentsUpperListCriterion2'}=join(':::', @upperStudents2);
+    $problemData{'studentsLowerListCriterion2'}=join(':::', @lowerStudents2);
+
+    $problemData{'problemList'} = join(':::', @problemList);
+#                $Discussed=0;
+#                if($Discuss->{"$name:$problem"}) {
+#		    $TotDiscuss++;
+#                    $Discussed=1;
+#                }
+
+    return \%problemData;
+}
+
+sub SortDivideByTries {
+    my ($toSort, $data, $sortOn)=@_;
+    my @orderedData = sort { ($data->{$a.':totalTries'}) ? 
+                             ($data->{$a.$sortOn}/$data->{$a.':totalTries'}):0
+                             <=>
+                             ($data->{$b.':totalTries'}) ? 
+                             ($data->{$b.$sortOn}/$data->{$b.':totalTries'}):0
+                           } @$toSort;
+
+    return \@orderedData;
+}
+
+sub SortProblems {
+    my ($problemData,$sortBy,$ascend)=@_;
+
+    my @problems = split(':::', $problemData->{'problemList'});
+    if($sortBy eq "Homework Sets Order") {
+        return \@problems;
+    }
+
+    my $data;
+
+    if   ($sortBy eq "#Stdnts") { $data = ':studentCount'; }
+    elsif($sortBy eq "Tries")   { $data = ':totalTries'; }
+    elsif($sortBy eq "Mod")     { $data = ':maxTries'; }
+    elsif($sortBy eq "Mean")    { $data = ':mean'; }
+    elsif($sortBy eq "#YES")    { $data = ':correct'; }
+    elsif($sortBy eq "#yes")    { $data = ':correctByOverride'; }
+    elsif($sortBy eq "%Wrng")   { $data = ':percentWrong'; }
+    elsif($sortBy eq "DoDiff")  { $data = ':degreeOfDifficulty'; }
+    elsif($sortBy eq "S.D.")    { $data = ':standardDeviation'; }
+    elsif($sortBy eq "Skew.")   { $data = ':skewness'; }
+    elsif($sortBy eq "D.F.1st") { $data = ':discriminantFactor1'; }
+    elsif($sortBy eq "D.F.2nd") { $data = ':discriminantFactor2'; }
+    elsif($sortBy eq "Disc.")   { $data = ''; }
+    else                        { return \@problems; }
+
+    my @orderedProblems = 
+        sort { $problemData->{$a.$data} <=> $problemData->{$b.$data} }
+             @problems;
+    if($ascend eq 'Descending') {
+        @orderedProblems = reverse(@orderedProblems);
+    }
+
+    return \@orderedProblems;
+}
+
+sub CalculateStatistics {
+    my ($data, $cache)=@_;
+
+    my @problems = split(':::', $data->{'problemList'});
+    foreach(@problems) {
+        # Mean
+        $data->{$_.':mean'} = ($data->{$_.':studentCount'}) ? 
+            ($data->{$_.':totalTries'} / $data->{$_.':studentCount'}) : 0;
+
+        # %Wrong
+        $data->{$_.':percentWrong'} = ($data->{$_.':studentCount'}) ?
+            (($data->{$_.':wrong'} / $data->{$_.':studentCount'}) * 100.0) : 
+            100.0;
+
+        # Degree of Difficulty
+        $data->{$_.':degreeOfDifficulty'} = ($data->{$_.':totalTries'}) ?
+            (1 - (($data->{$_.':correct'} + $data->{$_.':correctByOverride'}) /
+                  $data->{$_.':totalTries'})) : 0;
+
+        # Factor in mean
+        my $studentTries = $data->{$_.':studentTries'};
+        foreach(my $index=0; $index < scalar(@$studentTries); $index++) {
+            $studentTries->[$index] -= $data->{$_.':mean'};
+        }
+        my $sumSquared = 0;
+        my $sumCubed = 0;
+        foreach(@$studentTries) {
+            my $squared = ($_ * $_);
+            my $cubed = ($squared * $_);
+            $sumSquared += $squared;
+            $sumCubed += $cubed;
+        }
+
+        # Standard deviation
+        $data->{$_.':standardDeviation'} = ($data->{$_.':studentCount'} - 1) ?
+            ((sqrt($sumSquared)) / ($data->{$_.':studentCount'} - 1)) : 0;
+
+        # Skewness
+        my $standardDeviation = $data->{$_.':standardDeviation'};
+        $data->{$_.':skewness'} = ($data->{$_.':standardDeviation'}) ?
+            (((sqrt($sumSquared)) / $data->{$_.':studentCount'}) / 
+             ($standardDeviation * $standardDeviation * $standardDeviation)) :
+             0;
+
+        # Discrimination Factor 1
+        my ($sequence, $problem, $part) = split(':', $_);
+
+        my @upper1 = split(':::', $data->{'studentsUpperListCriterion1'});
+        my @lower1 = split(':::', $data->{'studentsLowerListCriterion1'});
+
+        my $upper1Sum=0;
+        foreach my $name (@upper1) {
+            $upper1Sum += $cache->{"$name:$problem:$part:awarded"};
+        }
+        $upper1Sum /= (scalar(@upper1)) ? (scalar(@upper1)) : 0;
+
+        my $lower1Sum=0;
+        foreach my $name (@lower1) {
+            $lower1Sum += $cache->{"$name:$problem:$part:awarded"};
+        }
+        $lower1Sum /= (scalar(@lower1)) ? (scalar(@lower1)) : 0;
+
+        $data->{$_.':discriminationFactor1'} = $upper1Sum - $lower1Sum;
+
+        # Discrimination Factor 2
+        my @upper2 = split(':::', $data->{'studentsUpperListCriterion2'});
+        my @lower2 = split(':::', $data->{'studentsLowerListCriterion2'});
+
+        my $upper2Sum=0;
+        foreach my $name (@upper2) {
+            $upper2Sum += $cache->{"$name:$problem:$part:awarded"};
+        }
+        $upper2Sum /= (scalar(@upper2)) ? (scalar(@upper2)) : 0;
+
+        my $lower2Sum=0;
+        foreach my $name (@lower2) {
+            $lower2Sum += $cache->{"$name:$problem:$part:awarded"};
+        }
+        $lower2Sum /= (scalar(@lower2)) ? (scalar(@lower2)) : 0;
+
+        $data->{$_.':discriminationFactor2'} = $upper2Sum - $lower2Sum;
+    }
+
+    return;
 }
+
+#---- END Problem Statistics Web Page ----------------------------------------
+
 1;
 __END__