'.
+ &mt('Press "Generate Statistics" when you are ready.').
+ '
'.
+ &mt('It may take some time to update the student data '.
+ 'for the first analysis. Future analysis this session '.
+ ' will not have this delay.').
+ '
');
+ return;
+ }
+ $r->rflush();
+ #
+ # This probably does not need to be done each time we are called, but
+ # it does not slow things down noticably.
+ &Apache::loncoursedata::populate_weight_table();
+ #
+ if (exists($ENV{'form.Excel'})) {
+ &Excel_output($r);
+ } else {
+ $r->print(''.' 'x5);
+ $r->rflush();
+ my $count = 0;
+ ($navmap,@sequences) =
+ &Apache::lonstatistics::selected_sequences_with_assessments();
+ if (! ref($navmap)) {
+ $r->print('
\n";
+ my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+ if (defined($starttime) || defined($endtime)) {
+ # Inform the user what the time limits on the data are.
+ $Str .= '
'.&mt('Statistics on submissions from [_1] to [_2]',
+ &Apache::lonlocal::locallocaltime($starttime),
+ &Apache::lonlocal::locallocaltime($endtime)
+ ).'
';
+ }
+ $Str .= "
".&mt('Compiled on [_1]',
+ &Apache::lonlocal::locallocaltime(time))."
'."\n";
+sub degrees_plot {
+ my ($r)=@_;
+ my $count = scalar(@StatsArray);
+ my $width = 50 + 10*$count;
+ $width = 300 if ($width < 300);
+ my $height = 300;
+ my $plot = '';
+ my $ymax = 0;
+ my $ymin = 0;
+ my @Disc; my @Diff; my @Labels;
+ foreach my $data (@StatsArray) {
+ push(@Labels,$data->{'problem_num'});
+ my $disc = $data->{'deg_of_disc'};
+ my $diff = $data->{'deg_of_diff'};
+ push(@Disc,$disc);
+ push(@Diff,$diff);
+ #
+ $ymin = $disc if ($ymin > $disc);
+ $ymin = $diff if ($ymin > $diff);
+ $ymax = $disc if ($ymax < $disc);
+ $ymax = $diff if ($ymax < $diff);
+ }
+ #
+ # Make sure we show relevant information.
+ if ($ymin < 0) {
+ if (abs($ymin) < 0.05) {
+ $ymin = 0;
+ } else {
+ $ymin = -1;
+ }
+ }
+ if ($ymax > 0) {
+ if (abs($ymax) < 0.05) {
+ $ymax = 0;
+ } else {
+ $ymax = 1;
+ }
+ }
+ #
+ my $xmax = $Labels[-1];
+ if ($xmax > 50) {
+ if ($xmax % 10 != 0) {
+ $xmax = 10 * (int($xmax/10)+1);
+ }
+ } else {
+ if ($xmax % 5 != 0) {
+ $xmax = 5 * (int($xmax/5)+1);
+ }
+ }
+ #
+ my $discdata .= ''.join(',',@Labels).''.$/.
+ ''.join(',',@Disc).''.$/;
+ #
+ my $diffdata .= ''.join(',',@Labels).''.$/.
+ ''.join(',',@Diff).''.$/;
+ #
+ my $title = 'Degree of Discrimination\nand Degree of Difficulty';
+ if ($xmax > 50) {
+ $title = 'Degree of Discrimination and Degree of Difficulty';
+ }
+ #
+ $plot=<<"END";
+
+
+ $title
+
+ Problem Number
+
+ $discdata
+
+
+ $diffdata
+
+
+END
+ my $plotresult =
+ '
'.&Apache::lonxml::xmlparse($r,'web',$plot).'
'.$/;
+ $r->print($plotresult);
+ return;
+}
- return $Ptr;
+sub tries_data_plot {
+ my ($r)=@_;
+ my $count = scalar(@StatsArray);
+ my $width = 50 + 10*$count;
+ $width = 300 if ($width < 300);
+ my $height = 300;
+ my $plot = '';
+ my @STD; my @Mean; my @Max; my @Min;
+ my @Labels;
+ my $ymax = 5;
+ foreach my $data (@StatsArray) {
+ my $max = $data->{'mean_tries'} + $data->{'std_tries'};
+ $ymax = $max if ($ymax < $max);
+ $ymax = $max if ($ymax < $max);
+ push(@Labels,$data->{'problem_num'});
+ push(@STD,$data->{'std_tries'});
+ push(@Mean,$data->{'mean_tries'});
+ }
+ #
+ # Make sure we show relevant information.
+ my $xmax = $Labels[-1];
+ if ($xmax > 50) {
+ if ($xmax % 10 != 0) {
+ $xmax = 10 * (int($xmax/10)+1);
+ }
+ } else {
+ if ($xmax % 5 != 0) {
+ $xmax = 5 * (int($xmax/5)+1);
+ }
+ }
+ $ymax = int($ymax)+1+2;
+ #
+ my $std_data .= ''.join(',',@Labels).''.$/.
+ ''.join(',',@Mean).''.$/;
+ #
+ my $std_error_data .= ''.join(',',@Labels).''.$/.
+ ''.join(',',@Mean).''.$/.
+ ''.join(',',@STD).''.$/;
+ #
+ my $title = 'Mean and S.D. of Tries';
+ if ($xmax > 25) {
+ $title = 'Mean and Standard Deviation of Tries';
+ }
+ #
+ $plot=<<"END";
+
+ $title
+
+ Problem Number
+ Number of Tries
+
+ $std_error_data
+
+
+ $std_data
+
+
+END
+ my $plotresult =
+ '
'.&Apache::lonxml::xmlparse($r,'web',$plot).'
'.$/;
+ $r->print($plotresult);
+ return;
}
-sub AscendOrderOptions {
- my ($order)=@_;
+sub plot_dropdown {
+ my $current = '';
+ #
+ if (defined($ENV{'form.plot'})) {
+ $current = $ENV{'form.plot'};
+ }
+ #
+ my @Additional_Plots = (
+ { graphable=>'yes',
+ name => 'degrees',
+ title => 'Difficulty Indexes' },
+ { graphable=>'yes',
+ name => 'tries statistics',
+ title => 'Tries Statistics' });
+ #
+ my $Str= "\n".''."\n";
+ return $Str;
+}
- my $OpSel1 = '';
- my $OpSel2 = '';
+###############################################
+###############################################
+##
+## Excel output routines
+##
+###############################################
+###############################################
+sub Excel_output {
+ my ($r) = @_;
+ $r->print('
'.&mt('Preparing Excel Spreadsheet').'
');
+ ##
+ ## Compute the statistics
+ &compute_all_statistics($r);
+ my $c = $r->connection;
+ return if ($c->aborted());
+ ##
+ ## Create the excel workbook
+ my $filename = '/prtspool/'.
+ $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.
+ time.'_'.rand(1000000000).'.xls';
+ my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+ #
+ # Create sheet
+ my $excel_workbook = Spreadsheet::WriteExcel->new('/home/httpd'.$filename);
+ #
+ # Check for errors
+ if (! defined($excel_workbook)) {
+ $r->log_error("Error creating excel spreadsheet $filename: $!");
+ $r->print(&mt("Problems creating new Excel file. ".
+ "This error has been logged. ".
+ "Please alert your LON-CAPA administrator."));
+ return 0;
+ }
+ #
+ # The excel spreadsheet stores temporary data in files, then put them
+ # together. If needed we should be able to disable this (memory only).
+ # The temporary directory must be specified before calling 'addworksheet'.
+ # File::Temp is used to determine the temporary directory.
+ $excel_workbook->set_tempdir($Apache::lonnet::tmpdir);
+ #
+ # Add a worksheet
+ my $sheetname = $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
+ if (length($sheetname) > 31) {
+ $sheetname = substr($sheetname,0,31);
+ }
+ my $excel_sheet = $excel_workbook->addworksheet(
+ &Apache::loncommon::clean_excel_name($sheetname));
+ #
+ my $format = &Apache::loncommon::define_excel_formats($excel_workbook);
+ ##
+ ## Begin creating excel sheet
+ ##
+ my ($rows_output,$cols_output) = (0,0);
+ #
+ # Put the course description in the header
+ $excel_sheet->write($rows_output,$cols_output++,
+ $ENV{'course.'.$ENV{'request.course.id'}.'.description'},
+ $format->{'h1'});
+ $cols_output += 3;
+ #
+ # Put a description of the sections listed
+ my $sectionstring = '';
+ $excel_sheet->write($rows_output,$cols_output++,
+ &Apache::lonstathelpers::sections_description
+ (@Apache::lonstatistics::SelectedSections),
+ $format->{'h3'});
+ $cols_output += scalar(@Apache::lonstatistics::SelectedSections);
+ #
+ # Time restrictions
+ my $time_string;
+ if (defined($starttime)) {
+ # call localtime but not lonlocal:locallocaltime because excel probably
+ # cannot handle localized text. Probably.
+ $time_string .= 'Data collected from '.localtime($time_string);
+ if (defined($endtime)) {
+ $time_string .= ' to '.localtime($endtime);
+ }
+ $time_string .= '.';
+ } elsif (defined($endtime)) {
+ # See note above about lonlocal:locallocaltime
+ $time_string .= 'Data collected before '.localtime($endtime).'.';
+ }
+ if (defined($time_string)) {
+ $excel_sheet->write($rows_output,$cols_output++,$time_string);
+ $cols_output+= 5;
+ }
+ #
+ # Put the date in there too
+ $excel_sheet->write($rows_output,$cols_output++,
+ 'Compiled on '.localtime(time));
+ #
+ $rows_output++;
+ $cols_output=0;
+ ##
+ ## Sequence Statistics
+ ##
+ &write_headers($excel_sheet,$format,\$rows_output,\$cols_output,
+ \@SeqFields);
+ foreach my $seq (@sequences) {
+ my $data = $SeqStat{$seq->symb};
+ $cols_output=0;
+ foreach my $field (@SeqFields) {
+ next if ($field->{'selected'} ne 'yes');
+ my $fieldformat = undef;
+ if (exists($field->{'excel_format'})) {
+ $fieldformat = $format->{$field->{'excel_format'}};
+ }
+ $excel_sheet->write($rows_output,$cols_output++,
+ $data->{$field->{'name'}},$fieldformat);
+ }
+ $rows_output++;
+ $cols_output=0;
+ }
+ ##
+ ## Resource Statistics
+ ##
+ $rows_output++;
+ $cols_output=0;
+ &write_headers($excel_sheet,$format,\$rows_output,\$cols_output,
+ \@Fields);
+ #
+ foreach my $data (@StatsArray) {
+ $cols_output=0;
+ foreach my $field (@Fields) {
+ next if ($field->{'selected'} ne 'yes');
+ next if ($field->{'name'} eq 'problem_num');
+ my $fieldformat = undef;
+ if (exists($field->{'excel_format'})) {
+ $fieldformat = $format->{$field->{'excel_format'}};
+ }
+ $excel_sheet->write($rows_output,$cols_output++,
+ $data->{$field->{'name'}},$fieldformat);
+ }
+ $rows_output++;
+ $cols_output=0;
+ }
+ #
+ $excel_workbook->close();
+ #
+ # Tell the user where to get their excel file
+ $r->print(' '.
+ ''.
+ &mt('Your Excel Spreadsheet').''."\n");
+ $r->rflush();
+ return;
+}
- if($order eq 'Ascending') {
- $OpSel1 = ' selected';
- } else {
- $OpSel2 = ' selected';
+##
+## &write_headers
+##
+sub write_headers {
+ my ($excel_sheet,$format,$rows_output,$cols_output,$Fields) = @_;
+ ##
+ ## First the long titles
+ foreach my $field (@{$Fields}) {
+ next if ($field->{'name'} eq 'problem_num');
+ next if ($field->{'selected'} ne 'yes');
+ if (exists($field->{'long_title'})) {
+ $excel_sheet->write($$rows_output,${$cols_output},
+ $field->{'long_title'},
+ $format->{'bold'});
+ } else {
+ $excel_sheet->write($$rows_output,${$cols_output},'');
+ }
+ ${$cols_output}+= 1;
}
+ ${$cols_output} =0;
+ ${$rows_output}+=1;
+ ##
+ ## Then the short titles
+ foreach my $field (@{$Fields}) {
+ next if ($field->{'selected'} ne 'yes');
+ next if ($field->{'name'} eq 'problem_num');
+ # Use english for excel as I am not sure how well excel handles
+ # other character sets....
+ $excel_sheet->write($$rows_output,$$cols_output,
+ $field->{'title'},
+ $format->{'bold'});
+ $$cols_output+=1;
+ }
+ ${$cols_output} =0;
+ ${$rows_output}+=1;
+ return;
+}
- my $Ptr = '';
- $Ptr .= '
Sorting Type:
'."\n";
- $Ptr .= '
'."\n";
-
- return $Ptr;
-}
-
-sub ProblemStatisticsButtons {
- my ($displayFormat)=@_;
-
- my $Ptr = '
';
- $Ptr .= 'parts}) {
+ next if ($res->is_survey($part));
+ #
+ # This is where all the work happens
+ my $data = &get_statistics($seq,$res,$part,scalar(@StatsArray)+1);
+ push (@Data,$data);
+ push (@StatsArray,$data);
+ }
}
- $Ptr .= '
';
+ return @Data;
+}
- return $Ptr;
+sub compute_all_statistics {
+ my ($r) = @_;
+ if (@StatsArray > 0) {
+ # Assume we have already computed the statistics
+ return;
+ }
+ my $c = $r->connection;
+ foreach my $seq (@sequences) {
+ last if ($c->aborted);
+ &compute_sequence_statistics($seq);
+ &compute_statistics_on_sequence($seq);
+ }
}
-sub ProblemStatisticsLegend {
- my $Ptr = '';
- $Ptr = '
';
- $Ptr .= '
';
- $Ptr .= '#Stdnts
';
- $Ptr .= '
Total Number of Students opened the problem.';
- $Ptr .= '
';
- $Ptr .= 'Tries
';
- $Ptr .= '
Total Number of Tries for solving the problem.';
- $Ptr .= '
';
- $Ptr .= 'Mod
';
- $Ptr .= '
Maximunm Number of Tries for solving the problem.';
- $Ptr .= '
';
- $Ptr .= 'Mean
';
- $Ptr .= '
Average Number of the tries. [ Tries / #Stdnts ]';
- $Ptr .= '
';
- $Ptr .= '#YES
';
- $Ptr .= '
Number of students solved the problem correctly.';
- $Ptr .= '
';
- $Ptr .= '#yes
';
- $Ptr .= '
Number of students solved the problem by override.';
- $Ptr .= '
';
- $Ptr .= '%Wrng
';
- $Ptr .= '
Percentage of students tried to solve the problem ';
- $Ptr .= 'but still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]';
- $Ptr .= '
';
- $Ptr .= 'DoDiff
';
- $Ptr .= '
Degree of Difficulty of the problem. ';
- $Ptr .= '[ 1 - ((#YES+#yes) / Tries) ]';
- $Ptr .= '
';
- $Ptr .= 'S.D.
';
- $Ptr .= '
Standard Deviation of the tries. ';
- $Ptr .= '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1) ';
- $Ptr .= 'where Xi denotes every student\'s tries ]';
- $Ptr .= '
';
- $Ptr .= 'Skew.
';
- $Ptr .= '
Skewness of the students tries.';
- $Ptr .= '[(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]';
- $Ptr .= '
';
- $Ptr .= 'Dis.F.
';
- $Ptr .= '
Discrimination Factor: A Standard for evaluating the ';
- $Ptr .= 'problem according to a Criterion ';
- $Ptr .= '[Applied Criterion in %27 Upper Students - ';
- $Ptr .= 'Applied the same Criterion in %27 Lower Students] ';
- $Ptr .= '1st Criterion for Sorting the Students: ';
- $Ptr .= 'Sum of Partial Credit Awarded / Total Number of Tries ';
- $Ptr .= '2nd Criterion for Sorting the Students: ';
- $Ptr .= 'Total number of Correct Answers / Total Number of Tries';
- $Ptr .= '
';
- $Ptr .= '
Disc.
';
- $Ptr .= '
Number of Students had at least one discussion.';
- $Ptr .= '
';
-
- 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(" $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(" $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,$_); }
+sub sort_data {
+ my ($sortkey) = @_;
+ return if (! @StatsArray);
+ #
+ # Sort the data
+ my $sortby = undef;
+ foreach my $field (@Fields) {
+ if ($sortkey eq $field->{'name'}) {
+ $sortby = $field->{'name'};
+ }
+ }
+ if (! defined($sortby) || $sortby eq '' || $sortby eq 'problem_num') {
+ $sortby = 'container';
+ }
+ if ($sortby ne 'container') {
+ # $sortby is already defined, so we can charge ahead
+ if ($sortby =~ /^(title|part)$/i) {
+ # Alpha comparison
+ @StatsArray = sort {
+ lc($a->{$sortby}) cmp lc($b->{$sortby}) ||
+ lc($a->{'title'}) cmp lc($b->{'title'}) ||
+ lc($a->{'part'}) cmp lc($b->{'part'});
+ } @StatsArray;
+ } else {
+ # Numerical comparison
+ @StatsArray = sort {
+ my $retvalue = 0;
+ if ($b->{$sortby} eq 'nan') {
+ if ($a->{$sortby} ne 'nan') {
+ $retvalue = -1;
+ } else {
+ $retvalue = 0;
+ }
}
- }
+ if ($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'});
+ }
+ $retvalue;
+ } @StatsArray;
}
}
- my %DisUp = &ProcessDiscriminant(\@UpList,$r);
- my %DisLow = &ProcessDiscriminant(\@LowList,$r);
+ #
+ # Renumber the data set
+ my $count;
+ foreach my $data (@StatsArray) {
+ $data->{'problem_num'} = ++$count;
+ }
+ return;
+}
- return (\%DisUp, \%DisLow);
-}
+########################################################
+########################################################
-#---- END Problem Statistics Web Page ----------------------------------------
+=pod
-#---- Problem Statistics Graph Web Page --------------------------------------
+=item &get_statistics()
-# ------------------------------------------- Prepare data for Graphical chart
+Wrapper routine from the call to loncoursedata::get_problem_statistics.
+Calls lonstathelpers::get_time_limits() to limit the data set by time
+and &compute_discrimination_factor
-sub BuildDiffGraph {
- my ($r)=@_;
+Inputs: $sequence, $resource, $part, $problem_num
- my $graphData = &GetGraphData('DiffGraph', $r);
- return '';
-}
+Returns: Hash reference with statistics data from
+loncoursedata::get_problem_statistics.
-sub BuildWrongGraph {
- my ($r)=@_;
+=cut
- my $graphData = &GetGraphData('WrongGraph', $r);
- return '';
+########################################################
+########################################################
+sub get_statistics {
+ my ($sequence,$resource,$part,$problem_num) = @_;
+ #
+ my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+ my $symb = $resource->symb;
+ my $courseid = $ENV{'request.course.id'};
+ #
+ my $data = &Apache::loncoursedata::get_problem_statistics
+ (\@Apache::lonstatistics::SelectedSections,
+ $Apache::lonstatistics::enrollment_status,
+ $symb,$part,$courseid,$starttime,$endtime);
+ $data->{'symb'} = $symb;
+ $data->{'part'} = $part;
+ $data->{'problem_num'} = $problem_num;
+ $data->{'container'} = $sequence->compTitle;
+ $data->{'title'} = $resource->compTitle;
+ $data->{'title.link'} = $resource->src.'?symb='.
+ &Apache::lonnet::escape($resource->symb);
+ #
+ if ($SelectedFields{'deg_of_disc'}) {
+ $data->{'deg_of_disc'} =
+ &compute_discrimination_factor($resource,$part,$sequence);
+ }
+ #
+ # Store in metadata if computations were done for all students
+ if ($data->{'num_students'} > 1) {
+ my @Sections = @Apache::lonstatistics::SelectedSections;
+ my $sections = '"'.join(' ',@Sections).'"';
+ $sections =~ s/&+/_/g; # Ensure no special characters
+ $data->{'sections'}=$sections;
+ $data->{'course'} = $ENV{'request.course.id'};
+ my $urlres=(&Apache::lonnet::decode_symb($resource->symb))[2];
+ $data->{'urlres'}=$urlres;
+ my %storestats =
+ &LONCAPA::lonmetadata::dynamic_metadata_storage($data);
+ my ($dom,$user) = $urlres=~/^(\w+)\/(\w+)/;
+ &Apache::lonnet::put('nohist_resevaldata',\%storestats,$dom,$user);
+ }
+ #
+ $data->{'tries_per_correct'} = $data->{'tries'} /
+ ($data->{'num_solved'}+0.1);
+ #
+ # Get the due date for research purposes (commented out most of the time)
+# $data->{'duedate'} =
+# &Apache::lonnet::EXT('resource.'.$part.'.duedate',$symb);
+# $data->{'opendate'} =
+# &Apache::lonnet::EXT('resource.'.$part.'.opendate',$symb);
+# $data->{'maxtries'} =
+# &Apache::lonnet::EXT('resource.'.$part.'.maxtries',$symb);
+# $data->{'hinttries'} =
+# &Apache::lonnet::EXT('resource.'.$part.'.hinttries',$symb);
+ $data->{'weight'} =
+ &Apache::lonnet::EXT('resource.'.$part.'.weight',$symb);
+# $data->{'resptypes'} = join(',',@{$resource->{'partdata'}->{$part}->{'ResponseTypes'}});
+ return $data;
}
+###############################################
+###############################################
+
+=pod
+
+=item &compute_discrimination_factor()
+
+Inputs: $Resource, $Sequence
+
+Returns: integer between -1 and 1
+
+=cut
-sub GetGraphData {
- my ($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 {
- $r->print("Unable to tie hash to db file");
- }
+###############################################
+###############################################
+sub compute_discrimination_factor {
+ my ($resource,$part,$seq) = @_;
+ my $symb = $resource->symb;
+ my @Resources;
+ foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)){
+ next if ($res->symb eq $symb);
+ push (@Resources,$res->symb);
+ }
+ #
+ # rank
+ my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+ my $ranking =
+ &Apache::loncoursedata::rank_students_by_scores_on_resources
+ (\@Resources,
+ \@Apache::lonstatistics::SelectedSections,
+ $Apache::lonstatistics::enrollment_status,undef,
+ $starttime,$endtime);
+ #
+ # compute their percent scores on the problems in the sequence,
+ my $number_to_grab = int(scalar(@{$ranking})/4);
+ my $num_students = scalar(@{$ranking});
+ my @BottomSet = map { $_->[&Apache::loncoursedata::RNK_student()];
+ } @{$ranking}[0..$number_to_grab];
+ my @TopSet =
+ map {
+ $_->[&Apache::loncoursedata::RNK_student()];
+ } @{$ranking}[($num_students-$number_to_grab)..($num_students-1)];
+ if (! @BottomSet || (@BottomSet == 1 && $BottomSet[0] eq '') ||
+ ! @TopSet || (@TopSet == 1 && $TopSet[0] eq '')) {
+ return 'nan';
+ }
+ my ($bottom_sum,$bottom_max) =
+ &Apache::loncoursedata::get_sum_of_scores($symb,$part,\@BottomSet,
+ undef,$starttime,$endtime);
+ my ($top_sum,$top_max) =
+ &Apache::loncoursedata::get_sum_of_scores($symb,$part,\@TopSet,
+ undef,$starttime,$endtime);
+ my $deg_of_disc;
+ if ($top_max == 0 || $bottom_max==0) {
+ $deg_of_disc = 'nan';
+ } else {
+ $deg_of_disc = ($top_sum/$top_max) - ($bottom_sum/$bottom_max);
+ }
+ #&Apache::lonnet::logthis(' '.$top_sum.'/'.$top_max.
+ # ' - '.$bottom_sum.'/'.$bottom_max);
+ return $deg_of_disc;
+}
+
+###############################################
+###############################################
+##
+## Compute KR-21
+##
+## To compute KR-21, you need the following information:
+##
+## K=the number of items in your test
+## M=the mean score on the test
+## s=the standard deviation of the scores on your test
+##
+## then:
+##
+## KR-21 rk= [K/(K-1)] * [1- (M*(K-M))/(K*s^2))]
+##
+###############################################
+###############################################
+sub compute_sequence_statistics {
+ my ($seq) = @_;
+ my $symb = $seq->symb;
+ my @Resources;
+ my $part_count;
+ foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)) {
+ push (@Resources,$res->symb);
+ $part_count += scalar(@{$res->parts});
+ }
+ my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
+ #
+ # First compute statistics based on student scores
+ my ($smin,$smax,$sMean,$sSTD,$scount,$sMAX) =
+ &Apache::loncoursedata::score_stats
+ (\@Apache::lonstatistics::SelectedSections,
+ $Apache::lonstatistics::enrollment_status,
+ \@Resources,$starttime,$endtime,undef);
+ $SeqStat{$symb}->{'title'} = $seq->compTitle;
+ $SeqStat{$symb}->{'scoremax'} = $smax;
+ $SeqStat{$symb}->{'scoremin'} = $smin;
+ $SeqStat{$symb}->{'scoremean'} = $sMean;
+ $SeqStat{$symb}->{'scorestd'} = $sSTD;
+ $SeqStat{$symb}->{'scorecount'} = $scount;
+ $SeqStat{$symb}->{'max_possible'} = $sMAX;
+ #
+ # Compute statistics based on the number of correct problems
+ # 'correct' is taken to mean
+ my ($cmin,$cmax,$cMean,$cSTD,$ccount)=
+ &Apache::loncoursedata::count_stats
+ (\@Apache::lonstatistics::SelectedSections,
+ $Apache::lonstatistics::enrollment_status,
+ \@Resources,$starttime,$endtime,undef);
+ my $K = $part_count;
+ my $kr_21;
+ if ($K > 1 && $cSTD > 0) {
+ $kr_21 = ($K/($K-1)) * (1 - $cMean*($K-$cMean)/($K*$cSTD**2));
+ } else {
+ $kr_21 = 'nan';
}
+ $SeqStat{$symb}->{'countmax'} = $cmax;
+ $SeqStat{$symb}->{'countmin'} = $cmin;
+ $SeqStat{$symb}->{'countstd'} = $cSTD;
+ $SeqStat{$symb}->{'countmean'} = $cMean;
+ $SeqStat{$symb}->{'count'} = $ccount;
+ $SeqStat{$symb}->{'items'} = $K;
+ $SeqStat{$symb}->{'KR-21'}=$kr_21;
+ return;
}
+
+=pod
+
+=item ProblemStatisticsLegend
+
+=over 4
+
+=item #Stdnts
+Total number of students attempted the problem.
+
+=item Tries
+Total number of tries for solving the problem.
+
+=item Max Tries
+Largest number of tries for solving the problem by a student.
+
+=item Mean
+Average number of tries. [ Tries / #Stdnts ]
+
+=item #YES
+Number of students solved the problem correctly.
+
+=item #yes
+Number of students solved the problem by override.
+
+=item %Wrong
+Percentage of students who tried to solve the problem
+but is still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]
+
+=item DoDiff
+Degree of Difficulty of the problem.
+[ 1 - ((#YES+#yes) / Tries) ]
+
+=item S.D.
+Standard Deviation of the tries.
+[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1)
+where Xi denotes every student\'s tries ]
+
+=item Skew.
+Skewness of the students tries.
+[(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]
+
+=item Dis.F.
+Discrimination Factor: A Standard for evaluating the
+problem according to a Criterion
+
+=item [Criterion to group students into %27 Upper Students -
+and %27 Lower Students]
+1st Criterion for Sorting the Students:
+Sum of Partial Credit Awarded / Total Number of Tries
+2nd Criterion for Sorting the Students:
+Total number of Correct Answers / Total Number of Tries
+
+=item Disc.
+Number of Students had at least one discussion.
+
+=back
+
+=cut
+
+############################################################
+############################################################
+
1;
__END__
';
-}
+Returns: Hash reference with statistics data from
+loncoursedata::get_problem_statistics.
-sub BuildWrongGraph {
- my ($r)=@_;
+=cut
- my $graphData = &GetGraphData('WrongGraph', $r);
- return '