File:
[LON-CAPA] /
loncom /
interface /
statistics /
lonproblemstatistics.pm
Revision
1.105:
download - view:
text,
annotated -
select for diffs
Fri Aug 26 21:53:23 2005 UTC (18 years, 8 months ago) by
albertel
Branches:
MAIN
CVS tags:
version_2_1_X,
version_2_1_3,
version_2_1_2,
version_2_1_1,
version_2_1_0,
version_2_0_X,
version_2_0_99_1,
version_2_0_2,
version_2_0_1,
HEAD
- some stat reports were not cleaningup the navmap cglobal which menat the course hashes weren't untied
# The LearningOnline Network with CAPA
#
# $Id: lonproblemstatistics.pm,v 1.105 2005/08/26 21:53:23 albertel Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
# (Navigate problems for statistical reports
#
###############################################
###############################################
=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 Apache::lonstatistics;
use LONCAPA::lonmetadata();
use Apache::lonlocal;
use Spreadsheet::WriteExcel;
use Apache::lonstathelpers();
use Time::HiRes;
my @StatsArray;
my %SeqStat; # keys are symbs, values are hash refs
##
## Localization notes:
##
## in @Fields[0]->{'long_title'} is placed in Excel files and is used as the
## header for plots created with Graph.pm, both of which more than likely do
## not support localization.
##
#
#
##
## Description of Field attributes
##
## Attribute Required Value Meaning or Use
##
## name yes any scalar Used to uniquely identify field
## title yes any scalar This is what the user sees to identify
## the field. Passed through &mt().
## long_title yes any scalar Used as graph heading and in excel
## output. NOT translated
## align no (left|right|center) HTML cell contents alignment
## color yes html color HTML cell background color
## used to visually group statistics
## special no (link) Indicates a link, target is name.link
## Currently set in &get_statistics()
## graphable no (yes|no) Can a bar graph of the field be
## produced?
## sortable no (yes|no) Should a sort link be put in the
## column header?
## selectable yes (yes|no) Can the column be removed from the
## statistics display?
## selected yes (yes|no) Is the column selected by default?
##
## format no sprintf format string
##
## excel_format no excel format type
## (see &Apache::loncommon::define_excel_formats
my @Fields = (
{ name => 'problem_num',
title => 'P#',
align => 'right',
color => '#FFFFE6',
selectable => 'no',
defaultselected => 'yes',
},
{ name => 'container',
title => 'Sequence or Folder',
align => 'left',
color => '#FFFFE6',
sortable => 'yes',
selectable => 'no',
defaultselected => 'yes',
},
{ name => 'title',
title => 'Title',
align => 'left',
color => '#FFFFE6',
special => 'link',
sortable => 'yes',
selectable => 'no',
defaultselected => 'yes',
},
{ name => 'part',
title => 'Part',
align => 'left',
color => '#FFFFE6',
selectable => 'no',
defaultselected => 'yes',
},
{ name => 'num_students',
title => '#Stdnts',
align => 'right',
color => '#EEFFCC',
format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Number of Students Attempting Problem',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'tries',
title => 'Tries',
align => 'right',
color => '#EEFFCC',
format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Total Number of Tries',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'max_tries',
title => 'Max Tries',
align => 'right',
color => '#DDFFFF',
format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Maximum Number of Tries',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'min_tries',
title => 'Min Tries',
align => 'right',
color => '#DDFFFF',
format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Minumum Number of Tries',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'mean_tries',
title => 'Mean Tries',
align => 'right',
color => '#DDFFFF',
format => '%5.2f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Average Number of Tries',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'std_tries',
title => 'S.D. tries',
align => 'right',
color => '#DDFFFF',
format => '%5.2f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Standard Deviation of Number of Tries',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'skew_tries',
title => 'Skew Tries',
align => 'right',
color => '#DDFFFF',
format => '%5.2f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Skew of Number of Tries',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'num_solved',
title => '#YES',
align => 'right',
color => '#FFDDDD',
format => '%4.1f',# format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Number of Students able to Solve',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'num_override',
title => '#yes',
align => 'right',
color => '#FFDDDD',
format => '%4.1f',# format => '%d',
sortable => 'yes',
graphable => 'yes',
long_title => 'Number of Students given Override',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'tries_per_correct',
title => 'tries/correct',
align => 'right',
color => '#FFDDDD',
format => '%4.1f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Tries per Correct Answer',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'num_wrong',
title => '#Wrng',
align => 'right',
color => '#FFDDDD',
format => '%4.1f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Number of students whose final answer is wrong',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'per_wrong',
title => '%Wrng',
align => 'right',
color => '#FFDDDD',
format => '%4.1f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Percent of students whose final answer is wrong',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'deg_of_diff',
title => 'DoDiff',
align => 'right',
color => '#FFFFE6',
format => '%5.2f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Degree of Difficulty'.
'[ 1 - ((#YES+#yes) / Tries) ]',
selectable => 'yes',
defaultselected => 'yes',
},
{ name => 'deg_of_disc',
title => 'DoDisc',
align => 'right',
color => '#FFFFE6',
format => '%4.2f',
sortable => 'yes',
graphable => 'yes',
long_title => 'Degree of Discrimination',
selectable => 'yes',
defaultselected => 'yes',
},
## duedate included for research purposes. Commented out most of the time.
# { name => 'duedate',
# title => 'Due Date',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'yes',
# graphable => 'no',
# long_title => 'Due date of resource for instructor',
# selectable => 'no',
# defaultselected => 'yes',
# },
## opendate included for research purposes. Commented out most of the time.
# { name => 'opendate',
# title => 'Open Date',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'yes',
# graphable => 'no',
# long_title => 'date resource became answerable',
# selectable => 'no',
# defaultselected => 'yes',
# },
## symb included for research purposes. Commented out most of the time.
# { name => 'symb',
# title => 'Symb',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'yes',
# graphable => 'no',
# long_title => 'Unique LON-CAPA identifier for problem',
# selectable => 'no',
# defaultselected => 'yes',
# },
## resptypes included for research purposes. Commented out most of the time.
# { name => 'resptypes',
# title => 'Response Types',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'no',
# graphable => 'no',
# long_title => 'Response Types used in this problem',
# selectable => 'no',
# defaultselected => 'yes',
# },
## maxtries included for research purposes. Commented out most of the time.
# { name => 'maxtries',
# title => 'Maxtries',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'no',
# graphable => 'no',
# long_title => 'Maximum number of tries',
# selectable => 'no',
# defaultselected => 'yes',
# },
## hinttries included for research purposes. Commented out most of the time.
# { name => 'hinttries',
# title => 'hinttries',
# align => 'left',
# color => '#FFFFFF',
# sortable => 'no',
# graphable => 'no',
# long_title => 'Number of tries before a hint appears',
# selectable => 'no',
# defaultselected => 'yes',
# },
#
## problem weight for instructor
{ name => 'weight',
title => 'weight',
align => 'right',
color => '#FFFFFF',
sortable => 'no',
graphable => 'no',
long_title => 'Problem weight (for instructor)',
selectable => 'yes',
defaultselected => 'yes',
},
);
my @SeqFields = (
{ name => 'title',
title => 'Sequence',
align => 'left',
color => '#FFFFE6',
special => 'no',
sortable => 'no',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'items',
title => '#Items',
align => 'right',
color => '#FFFFE6',
format => '%4d',
sortable => 'no',
graphable => 'no',
long_title => 'Number of Items in Sequence',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'scoremean',
title => 'Score Mean',
align => 'right',
color => '#FFFFE6',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Mean Sequence Score',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'scorestd',
title => 'Score STD',
align => 'right',
color => '#FFFFE6',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Standard Deviation of Sequence Scores',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'scoremax',
title => 'Score Max',
align => 'right',
color => '#FFFFE6',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Maximum Sequence Score',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'scoremin',
title => 'Score Min',
align => 'right',
color => '#FFFFE6',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Minumum Sequence Score',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'scorecount',
title => 'Score N',
align => 'right',
color => '#FFFFE6',
format => '%4d',
sortable => 'no',
graphable => 'no',
long_title => 'Number of Students in score computations',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'countmean',
title => 'Count Mean',
align => 'right',
color => '#FFFFFF',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Mean Sequence Score',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'countstd',
title => 'Count STD',
align => 'right',
color => '#FFFFFF',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Standard Deviation of Sequence Scores',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'countmax',
title => 'Count Max',
align => 'right',
color => '#FFFFFF',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Maximum Number of Correct Problems',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'countmin',
title => 'Count Min',
align => 'right',
color => '#FFFFFF',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'Minumum Number of Correct Problems',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'count',
title => 'Count N',
align => 'right',
color => '#FFFFFF',
format => '%4d',
sortable => 'no',
graphable => 'no',
long_title => 'Number of Students in score computations',
selectable => 'yes',
defaultselected => 'no',
},
{ name => 'KR-21',
title => 'KR-21',
align => 'right',
color => '#FFAAAA',
format => '%4.2f',
sortable => 'no',
graphable => 'no',
long_title => 'KR-21 reliability statistic',
selectable => 'yes',
defaultselected => 'no',
},
);
my %SelectedFields;
sub parse_field_selection {
#
# Pull out the defaults
if (! defined($env{'form.fieldselections'})) {
$env{'form.fieldselections'} = [];
foreach my $field (@Fields) {
next if ($field->{'selectable'} ne 'yes');
if ($field->{'defaultselected'} eq 'yes') {
push(@{$env{'form.fieldselections'}},$field->{'name'});
}
}
}
#
# Make sure the data we are plotting is there
my %NeededFields;
if (exists($env{'form.plot'}) && $env{'form.plot'} ne '' &&
$env{'form.plot'} ne 'none') {
if ($env{'form.plot'} eq 'degrees') {
$NeededFields{'deg_of_diff'}++;
$NeededFields{'deg_of_disc'}++;
} elsif ($env{'form.plot'} eq 'tries statistics') {
$NeededFields{'mean_tries'}++;
$NeededFields{'std_tries'}++;
$NeededFields{'problem_num'}++;
} else {
$NeededFields{$env{'form.plot'}}++;
}
}
#
# This should not happen, but in case it does...
if (ref($env{'form.fieldselections'}) ne 'ARRAY') {
$env{'form.fieldselections'} = [$env{'form.fieldselections'}];
}
#
# Set the field data and the selected fields (for easier checking)
undef(%SelectedFields);
foreach my $field (@Fields) {
if ($field->{'selectable'} ne 'yes') {
$field->{'selected'} = 'yes';
} else {
$field->{'selected'} = 'no';
}
if (exists($NeededFields{$field->{'name'}})) {
$field->{'selected'} = 'yes';
$SelectedFields{$field->{'name'}}++;
}
foreach my $selection (@{$env{'form.fieldselections'}}) {
if ($selection eq $field->{'name'} || $selection eq 'all') {
$field->{'selected'} = 'yes';
$SelectedFields{$field->{'name'}}++;
}
}
}
#
# Always show all the sequence statistics (for now)
foreach my $field (@SeqFields) {
$field->{'selected'} = 'yes';
}
return;
}
sub field_selection_input {
my $Str = '<select name="fieldselections" multiple size="5">'."\n";
$Str .= '<option value="all">all</option>'."\n";
foreach my $field (@Fields) {
next if ($field->{'selectable'} ne 'yes');
$Str .= ' <option value="'.$field->{'name'}.'" ';
if ($field->{'selected'} eq 'yes') {
$Str .= 'selected ';
}
$Str .= '>'.$field->{'title'}.'</option>'."\n";
}
$Str .= "</select>\n";
}
###############################################
###############################################
=pod
=item &CreateInterface()
Create the main intereface for the statistics page. Allows the user to
select sections, maps, and output.
=cut
###############################################
###############################################
sub CreateInterface {
my ($r) = @_;
#
&parse_field_selection();
#
my $Str = '';
$Str .= &Apache::lonhtmlcommon::breadcrumbs
(undef,'Overall Problem Statistics','Statistics_Overall_Key');
$Str .= '<table cellspacing="5">'."\n";
$Str .= '<tr>';
$Str .= '<td align="center"><b>'.&mt('Sections').'</b></td>';
$Str .= '<td align="center"><b>'.&mt('Enrollment Status').'</b></td>';
$Str .= '<td align="center"><b>'.&mt('Sequences and Folders').'</b></td>';
$Str .= '<td align="center"><b>'.&mt('Statistics').'</b></td>';
$Str .= '<td rowspan="2">'.
&Apache::lonstathelpers::limit_by_time_form().'</td>';
$Str .= '</tr>'."\n";
#
$Str .= '<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">';
#
$Str .= &Apache::lonstatistics::map_select('Maps','multiple,all',5);
$Str .= '</td><td>'.&field_selection_input();
$Str .= '</td></tr>'."\n";
$Str .= '</table>'."\n";
#
$Str .= '<p>'.&mt('Status: [_1]',
'<input type="text" '.
'name="stats_status" size="60" value="" />'
).
'</nobr></p>';
#
$Str .= '<input type="submit" name="GenerateStatistics" value="'.
&mt('Generate Statistics').'" />';
$Str .= ' 'x5;
$Str .= 'Plot '.&plot_dropdown().(' 'x10);
#
return $Str;
}
###############################################
###############################################
=pod
=item &BuildProblemStatisticsPage()
Main interface to problem statistics.
=cut
###############################################
###############################################
my $navmap;
my @sequences;
sub clean_up {
undef($navmap);
undef(@sequences);
}
sub BuildProblemStatisticsPage {
my ($r,$c)=@_;
undef($navmap);
undef(@sequences);
#
my %Saveable_Parameters = ('Status' => 'scalar',
'statsoutputmode' => 'scalar',
'Section' => 'array',
'StudentData' => 'array',
'Maps' => 'array',
'fieldselections'=> 'array');
&Apache::loncommon::store_course_settings('statistics',
\%Saveable_Parameters);
&Apache::loncommon::restore_course_settings('statistics',
\%Saveable_Parameters);
#
&Apache::lonstatistics::PrepareClasslist();
#
# Clear the package variables
undef(@StatsArray);
undef(%SeqStat);
#
# Finally let the user know we are here
my $interface = &CreateInterface($r);
$r->print($interface);
$r->print('<input type="hidden" name="sortby" value="'.$env{'form.sortby'}.
'" />');
#
my @CacheButtonHTML =
&Apache::lonstathelpers::manage_caches($r,'Statistics','stats_status');
my $Str;
foreach my $html (@CacheButtonHTML) {
$Str.=$html.(' 'x5);
}
#
$r->print($Str);
if (! exists($env{'form.firstrun'})) {
$r->print('<h3>'.
&mt('Press "Generate Statistics" when you are ready.').
'</h3><p>'.
&mt('It may take some time to update the student data '.
'for the first analysis. Future analysis this session '.
' will not have this delay.').
'</p>');
&clean_up();
return;
}
$r->rflush();
#
# This probably does not need to be done each time we are called, but
# it does not slow things down noticably.
&Apache::loncoursedata::populate_weight_table();
#
($navmap,@sequences) =
&Apache::lonstatistics::selected_sequences_with_assessments();
if (! ref($navmap)) {
$r->print('<h1>'.&mt('A course-wide error occured.').'</h1>'.
'<h3>'.$navmap.'</h3>');
&clean_up();
return;
}
if (exists($env{'form.Excel'})) {
$r->print('<h4>'.
&Apache::lonstatistics::section_and_enrollment_description().
'</h4>');
&Excel_output($r);
} else {
$r->print('<input type="submit" name="Excel" value="'.
&mt('Produce Excel Output').'" />'.' 'x5);
$r->rflush();
$r->print('<h4>'.
&Apache::lonstatistics::section_and_enrollment_description().
'</h4>');
my $count = 0;
foreach my $seq (@sequences) {
my @resources =
&Apache::lonstathelpers::get_resources($navmap,$seq);
$count += scalar(@resources);
}
if ($count > 10) {
$r->print('<h2>'.
&mt('Compiling statistics for [_1] problems',$count).
'</h2>');
if ($count > 30) {
$r->print('<h3>'.&mt('This will take some time.').'</h3>');
}
$r->rflush();
}
#
my $sortby = $env{'form.sortby'};
$sortby = 'container' if (! defined($sortby) || $sortby =~ /^\s*$/);
my $plot = $env{'form.plot'};
if ($plot eq '' || $plot eq 'none') {
undef($plot);
}
if ($sortby eq 'container' && ! defined($plot)) {
&output_sequence_statistics($r);
&output_html_by_sequence($r);
} else {
if (defined($plot)) {
&make_plot($r,$plot);
}
&output_html_stats($r);
&output_sequence_statistics($r);
}
}
&clean_up();
return;
}
sub output_sequence_statistics {
my ($r) = @_;
my $c=$r->connection();
$r->print('<h2>'.&mt('Sequence Statistics').
&Apache::loncommon::help_open_topic('Statistics_Sequence').
'</h2>');
$r->print('<table border="0"><tr><td bgcolor="#777777">'."\n".
'<table border="0" cellpadding="3">'."\n".
'<tr bgcolor="#FFFFE6">');
$r->print(&sequence_html_header());
foreach my $seq (@sequences) {
last if ($c->aborted);
&compute_sequence_statistics($seq);
$r->print(&sequence_html_output($seq));
}
$r->print('</table>');
$r->print('</table>');
$r->rflush();
return;
}
##########################################################
##########################################################
##
## HTML output routines
##
##########################################################
##########################################################
sub output_html_by_sequence {
my ($r) = @_;
my $c = $r->connection();
$r->print(&html_preamble());
#
foreach my $seq (@sequences) {
last if ($c->aborted);
$r->print("<h3>".$seq->compTitle."</h3>".
'<table border="0"><tr><td bgcolor="#777777">'."\n".
'<table border="0" cellpadding="3">'."\n".
'<tr bgcolor="#FFFFE6">'.
&statistics_table_header('no container')."</tr>\n");
my @Data = &compute_statistics_on_sequence($seq);
foreach my $data (@Data) {
$r->print('<tr>'.&statistics_html_table_data($data,
'no container').
"</tr>\n");
}
$r->print('</table>'."\n".'</table>'."\n");
$r->rflush();
}
return;
}
sub output_html_stats {
my ($r)=@_;
&compute_all_statistics($r);
$r->print(&html_preamble());
&sort_data($env{'form.sortby'});
#
my $count=0;
foreach my $data (@StatsArray) {
if ($count++ % 50 == 0) {
$r->print("</table>\n</table>\n");
$r->print('<table border="0"><tr><td bgcolor="#777777">'."\n".
'<table border="0" cellpadding="3">'."\n".
'<tr bgcolor="#FFFFE6">'.
'<tr bgcolor="#FFFFE6">'.
&statistics_table_header().
"</tr>\n");
}
$r->print('<tr>'.&statistics_html_table_data($data)."</tr>\n");
}
$r->print("</table>\n</table>\n");
return;
}
sub html_preamble {
my $Str='';
$Str .= "<h2>".
$env{'course.'.$env{'request.course.id'}.'.description'}.
"</h2>\n";
my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
if (defined($starttime) || defined($endtime)) {
# Inform the user what the time limits on the data are.
$Str .= '<h3>'.&mt('Statistics on submissions from [_1] to [_2]',
&Apache::lonlocal::locallocaltime($starttime),
&Apache::lonlocal::locallocaltime($endtime)
).'</h3>';
}
$Str .= "<h3>".&mt('Compiled on [_1]',
&Apache::lonlocal::locallocaltime(time))."</h3>";
return $Str;
}
###############################################
###############################################
##
## Misc HTML output routines
##
###############################################
###############################################
sub statistics_html_table_data {
my ($data,$options) = @_;
my $row = '';
foreach my $field (@Fields) {
next if ($options =~ /no $field->{'name'}/);
next if ($field->{'selected'} ne 'yes');
$row .= '<td bgcolor="'.$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'}) && $data->{$field->{'name'}} !~ /[A-Z]/i) {
$row .= sprintf($field->{'format'},$data->{$field->{'name'}});
} else {
$row .= $data->{$field->{'name'}};
}
if (exists($field->{'special'}) && $field->{'special'} eq 'link') {
$row.= '</a>';
}
$row .= '</td>';
}
return $row;
}
sub statistics_table_header {
my ($options) = @_;
my $header_row;
foreach my $field (@Fields) {
next if ($options =~ /no $field->{'name'}/);
next if ($field->{'selected'} ne 'yes');
$header_row .= '<th>';
if (exists($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>';
}
return $header_row;
}
sub sequence_html_header {
my $Str .= '<tr>';
foreach my $field (@SeqFields) {
# next if ($field->{'selected'} ne 'yes');
$Str .= '<th bgcolor="'.$field->{'color'}.'"';
$Str .= '>'.$field->{'title'}.'</th>';
}
$Str .= '</tr>';
return $Str;
}
sub sequence_html_output {
my ($seq) = @_;
my $data = $SeqStat{$seq->symb};
my $row = '<tr>';
foreach my $field (@SeqFields) {
next if ($field->{'selected'} ne 'yes');
$row .= '<td bgcolor="'.$field->{'color'}.'"';
if (exists($field->{'align'})) {
$row .= ' align="'.$field->{'align'}.'"';
}
$row .= '>';
if (exists($field->{'format'})) {
$row .= sprintf($field->{'format'},$data->{$field->{'name'}});
} else {
$row .= $data->{$field->{'name'}};
}
$row .= '</td>';
}
$row .= '</tr>'."\n";
return $row;
}
####################################################
####################################################
##
## Plotting Routines
##
####################################################
####################################################
sub make_plot {
my ($r,$plot) = @_;
&compute_all_statistics($r);
&sort_data($env{'form.sortby'});
if ($plot eq 'degrees') {
°rees_plot($r);
} elsif ($plot eq 'tries statistics') {
&tries_data_plot($r);
} else {
&make_single_stat_plot($r,$plot);
}
return;
}
sub make_single_stat_plot {
my ($r,$datafield) = @_;
#
my $title; my $yaxis;
foreach my $field (@Fields) {
next if ($field->{'name'} ne $datafield);
$title = $field->{'long_title'};
$yaxis = $field->{'title'};
last;
}
if ($title eq '' || $yaxis eq '') {
# datafield is something we do not know enough about to plot
$r->print('<h3>'.
&mt('Unable to plot the requested statistic.').
'</h3>');
return;
}
#
# Build up the data sets to plot
my @Labels;
my @Data;
my $max = 1;
foreach my $data (@StatsArray) {
push(@Labels,$data->{'problem_num'});
push(@Data,$data->{$datafield});
if ($data->{$datafield}>$max) {
$max = $data->{$datafield};
}
}
foreach (1,2,3,4,5,10,15,20,25,40,50,75,100,150,200,250,300,500,600,750,
1000,1500,2000,2500,3000,3500,4000,5000,7500,10000,15000,20000) {
if ($max <= $_) {
$max = $_;
last;
}
}
if ($max > 20000) {
$max = 10000*(int($max/10000)+1);
}
#
$r->print("<p>".&Apache::loncommon::DrawBarGraph($title,
'Problem Number',
$yaxis,
$max,
undef, # colors
\@Labels,
\@Data)."</p>\n");
return;
}
sub degrees_plot {
my ($r)=@_;
my $count = scalar(@StatsArray);
my $width = 50 + 10*$count;
$width = 300 if ($width < 300);
my $height = 300;
my $plot = '';
my $ymax = 0;
my $ymin = 0;
my @Disc; my @Diff; my @Labels;
foreach my $data (@StatsArray) {
push(@Labels,$data->{'problem_num'});
my $disc = $data->{'deg_of_disc'};
my $diff = $data->{'deg_of_diff'};
push(@Disc,$disc);
push(@Diff,$diff);
#
$ymin = $disc if ($ymin > $disc);
$ymin = $diff if ($ymin > $diff);
$ymax = $disc if ($ymax < $disc);
$ymax = $diff if ($ymax < $diff);
}
#
# Make sure we show relevant information.
if ($ymin < 0) {
if (abs($ymin) < 0.05) {
$ymin = 0;
} else {
$ymin = -1;
}
}
if ($ymax > 0) {
if (abs($ymax) < 0.05) {
$ymax = 0;
} else {
$ymax = 1;
}
}
#
my $xmax = $Labels[-1];
if ($xmax > 50) {
if ($xmax % 10 != 0) {
$xmax = 10 * (int($xmax/10)+1);
}
} else {
if ($xmax % 5 != 0) {
$xmax = 5 * (int($xmax/5)+1);
}
}
#
my $discdata .= '<data>'.join(',',@Labels).'</data>'.$/.
'<data>'.join(',',@Disc).'</data>'.$/;
#
my $diffdata .= '<data>'.join(',',@Labels).'</data>'.$/.
'<data>'.join(',',@Diff).'</data>'.$/;
#
my $title = 'Degree of Discrimination\nand Degree of Difficulty';
if ($xmax > 50) {
$title = 'Degree of Discrimination and Degree of Difficulty';
}
#
$plot=<<"END";
<gnuplot
texfont="10"
fgcolor="x000000"
plottype="Cartesian"
font="large"
grid="on"
align="center"
border="on"
transparent="on"
alttag="Degree of Discrimination and Degree of Difficulty Plot"
samples="100"
bgcolor="xffffff"
height="$height"
width="$width">
<key
pos="top right"
title=""
box="off" />
<title>$title</title>
<axis xmin="0" ymin="$ymin" xmax="$xmax" ymax="$ymax" color="x000000" />
<xlabel>Problem Number</xlabel>
<curve
linestyle="linespoints"
name="DoDisc"
pointtype="0"
color="x000000">
$discdata
</curve>
<curve
linestyle="linespoints"
name="DoDiff"
pointtype="0"
color="xFF0000">
$diffdata
</curve>
</gnuplot>
END
my $plotresult =
'<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
$r->print($plotresult);
return;
}
sub tries_data_plot {
my ($r)=@_;
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 $std_data .= '<data>'.join(',',@Labels).'</data>'.$/.
'<data>'.join(',',@Mean).'</data>'.$/;
#
my $std_error_data .= '<data>'.join(',',@Labels).'</data>'.$/.
'<data>'.join(',',@Mean).'</data>'.$/.
'<data>'.join(',',@STD).'</data>'.$/;
#
my $title = 'Mean and S.D. of Tries';
if ($xmax > 25) {
$title = 'Mean and Standard Deviation of Tries';
}
#
$plot=<<"END";
<gnuplot
texfont="10"
fgcolor="x000000"
plottype="Cartesian"
font="large"
grid="on"
align="center"
border="on"
transparent="on"
alttag="Mean and S.D of Tries Plot"
samples="100"
bgcolor="xffffff"
height="$height"
width="$width">
<title>$title</title>
<axis xmin="0" ymin="0" xmax="$xmax" ymax="$ymax" color="x000000" />
<xlabel>Problem Number</xlabel>
<ylabel>Number of Tries</ylabel>
<curve
linestyle="yerrorbars"
name="S.D. Tries"
pointtype="1"
color="x666666">
$std_error_data
</curve>
<curve
linestyle="points"
name="Mean Tries"
pointtype="1"
color="xCC4444">
$std_data
</curve>
</gnuplot>
END
my $plotresult =
'<p>'.&Apache::lonxml::xmlparse($r,'web',$plot).'</p>'.$/;
$r->print($plotresult);
return;
}
sub plot_dropdown {
my $current = '';
#
if (defined($env{'form.plot'})) {
$current = $env{'form.plot'};
}
#
my @Additional_Plots = (
{ graphable=>'yes',
name => 'degrees',
title => 'Difficulty Indexes' },
{ graphable=>'yes',
name => 'tries statistics',
title => 'Tries Statistics' });
#
my $Str= "\n".'<select name="plot" size="1">';
$Str .= '<option name="none"></option>'."\n";
$Str .= '<option name="none2">none</option>'."\n";
foreach my $field (@Additional_Plots,@Fields) {
if (! exists($field->{'graphable'}) ||
$field->{'graphable'} ne 'yes') {
next;
}
$Str .= '<option value="'.$field->{'name'}.'"';
if ($field->{'name'} eq $current) {
$Str .= ' selected ';
}
$Str.= '>'.&mt($field->{'title'}).'</option>'."\n";
}
$Str .= '</select>'."\n";
return $Str;
}
###############################################
###############################################
##
## Excel output routines
##
###############################################
###############################################
sub Excel_output {
my ($r) = @_;
$r->print('<h2>'.&mt('Preparing Excel Spreadsheet').'</h2>');
##
## Compute the statistics
&compute_all_statistics($r);
my $c = $r->connection;
return if ($c->aborted());
#
my ($starttime,$endtime) = &Apache::lonstathelpers::get_time_limits();
##
## Create the excel workbook
my ($excel_workbook,$filename,$format) =
&Apache::loncommon::create_workbook($r);
return if (! defined($excel_workbook));
#
# Add a worksheet
my $sheetname = $env{'course.'.$env{'request.course.id'}.'.description'};
if (length($sheetname) > 31) {
$sheetname = substr($sheetname,0,31);
}
my $excel_sheet = $excel_workbook->addworksheet(
&Apache::loncommon::clean_excel_name($sheetname));
##
## Begin creating excel sheet
##
my ($rows_output,$cols_output) = (0,0);
#
# Put the course description in the header
$excel_sheet->write($rows_output,$cols_output++,
$env{'course.'.$env{'request.course.id'}.'.description'},
$format->{'h1'});
$cols_output += 3;
#
# Put a description of the sections listed
my $sectionstring = '';
$excel_sheet->write($rows_output,$cols_output++,
&Apache::lonstatistics::section_and_enrollment_description('plaintext'),
$format->{'h3'});
$cols_output += scalar(&Apache::lonstatistics::get_selected_sections());
#
# 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
$r->print('<br />'.
'<a href="'.$filename.'">'.
&mt('Your Excel Spreadsheet').'</a>'."\n");
$r->rflush();
return;
}
##
## &write_headers
##
sub write_headers {
my ($excel_sheet,$format,$rows_output,$cols_output,$Fields) = @_;
##
## First the long titles
foreach my $field (@{$Fields}) {
next if ($field->{'name'} eq 'problem_num');
next if ($field->{'selected'} ne 'yes');
if (exists($field->{'long_title'})) {
$excel_sheet->write($$rows_output,${$cols_output},
$field->{'long_title'},
$format->{'bold'});
} else {
$excel_sheet->write($$rows_output,${$cols_output},'');
}
${$cols_output}+= 1;
}
${$cols_output} =0;
${$rows_output}+=1;
##
## Then the short titles
foreach my $field (@{$Fields}) {
next if ($field->{'selected'} ne 'yes');
next if ($field->{'name'} eq 'problem_num');
# Use english for excel as I am not sure how well excel handles
# other character sets....
$excel_sheet->write($$rows_output,$$cols_output,
$field->{'title'},
$format->{'bold'});
$$cols_output+=1;
}
${$cols_output} =0;
${$rows_output}+=1;
return;
}
##################################################
##################################################
##
## Statistics Gathering and Manipulation Routines
##
##################################################
##################################################
sub compute_statistics_on_sequence {
my ($seq) = @_;
my @Data;
foreach my $res (&Apache::lonstathelpers::get_resources($navmap,$seq)) {
foreach my $part (@{$res->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);
}
}
return @Data;
}
sub compute_all_statistics {
my ($r) = @_;
if (@StatsArray > 0) {
# Assume we have already computed the statistics
return;
}
my $c = $r->connection;
foreach my $seq (@sequences) {
last if ($c->aborted);
&compute_sequence_statistics($seq);
&compute_statistics_on_sequence($seq);
}
}
sub sort_data {
my ($sortkey) = @_;
return if (! @StatsArray);
#
# Sort the data
my $sortby = undef;
foreach my $field (@Fields) {
if ($sortkey eq $field->{'name'}) {
$sortby = $field->{'name'};
}
}
if (! defined($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;
}
}
#
# Renumber the data set
my $count;
foreach my $data (@StatsArray) {
$data->{'problem_num'} = ++$count;
}
return;
}
########################################################
########################################################
=pod
=item &get_statistics()
Wrapper routine from the call to loncoursedata::get_problem_statistics.
Calls lonstathelpers::get_time_limits() to limit the data set by time
and &compute_discrimination_factor
Inputs: $sequence, $resource, $part, $problem_num
Returns: Hash reference with statistics data from
loncoursedata::get_problem_statistics.
=cut
########################################################
########################################################
sub get_statistics {
my ($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::get_selected_sections()],
$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::get_selected_sections();
my $sections = '"'.join(' ',@Sections).'"';
$sections =~ s/&+/_/g; # Ensure no special characters
$data->{'sections'}=$sections;
$data->{'course'} = $env{'request.course.id'};
my $urlres=(&Apache::lonnet::decode_symb($resource->symb))[2];
$data->{'urlres'}=$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, $Sequence
Returns: integer between -1 and 1
=cut
###############################################
###############################################
sub compute_discrimination_factor {
my ($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::get_selected_sections()],
$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::get_selected_sections()],
$Apache::lonstatistics::enrollment_status,
\@Resources,$starttime,$endtime,undef);
$SeqStat{$symb}->{'title'} = $seq->compTitle;
$SeqStat{$symb}->{'scoremax'} = $smax;
$SeqStat{$symb}->{'scoremin'} = $smin;
$SeqStat{$symb}->{'scoremean'} = $sMean;
$SeqStat{$symb}->{'scorestd'} = $sSTD;
$SeqStat{$symb}->{'scorecount'} = $scount;
$SeqStat{$symb}->{'max_possible'} = $sMAX;
#
# Compute statistics based on the number of correct problems
# 'correct' is taken to mean
my ($cmin,$cmax,$cMean,$cSTD,$ccount)=
&Apache::loncoursedata::count_stats
([&Apache::lonstatistics::get_selected_sections()],
$Apache::lonstatistics::enrollment_status,
\@Resources,$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<br>
=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__
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