"); - $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,$_); } - } - } - } - } - my %DisUp = &ProcessDiscriminant(\@UpList); - my %DisLow = &ProcessDiscriminant(\@LowList); +=item Tries +Total number of tries for solving the problem. - return (\%DisUp, \%DisLow); -} +=item Max Tries +Largest number of tries for solving the problem by a student. - +=item Mean +Average number of tries. [ Tries / #Stdnts ] -#---- END Problem Statistics Web Page ---------------------------------------- +=item #YES +Number of students solved the problem correctly. -#---- Problem Statistics Graph Web Page -------------------------------------- +=item #yes +Number of students solved the problem by override. -# ------------------------------------------- Prepare data for Graphical chart +=item %Wrong +Percentage of students who tried to solve the problem +but is still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ] -sub BuildDiffGraph { - my ($r)=@_; +=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
- my $graphData = &GetGraphData('DiffGraph', $r); - return '
';
+=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
+
+
+############################################################
+############################################################
+##
+## How this all works:
+## Statistics are computed by calling &get_statistics with the sequence,
+## resource, and part id to run statistics on. At various places within
+## the loops which compute the statistics, as well as before and after
+## the entire process, subroutines can be called. The subroutines are
+## registered to the following hooks:
+##
+## hook subroutine inputs
+## ----------------------------------------------------------
+## pre $r,$count
+## pre_seq $r,$count,$seq
+## pre_res $r,$count,$seq,$res
+## calc $r,$count,$seq,$res,$data
+## post_res $r,$count,$seq,$res
+## post_seq $r,$count,$seq
+## post $r,$count
+##
+## abort $r
+##
+## subroutines will be called in the order in which they are registered.
+##
+############################################################
+############################################################
+{
+
+my %hooks;
+my $aborted = 0;
+
+sub abort_computation {
+ $aborted = 1;
}
-sub BuildWrongGraph {
- my ($r)=@_;
+sub clear_hooks {
+ $aborted = 0;
+ undef(%hooks);
+}
- my $graphData = &GetGraphData('WrongGraph', $r);
- return '';
+sub register_hook {
+ my ($hookname,$subref)=@_;
+ if ($hookname !~ /^(pre|pre_seq|pre_res|post|post_seq|post_res|calc)$/){
+ return;
+ }
+ if (ref($subref) ne 'CODE') {
+ &Apache::lonnet::logthis('attempt to register hook to non-code: '.
+ $hookname,' = '.$subref);
+ } else {
+ if (exists($hooks{$hookname})) {
+ push(@{$hooks{$hookname}},$subref);
+ } else {
+ $hooks{$hookname} = [$subref];
+ }
+ }
+ return;
}
+sub run_hooks {
+ my $context = shift();
+ foreach my $hook (@{$hooks{$context}}) {
+ if ($aborted && $context ne 'abort') {
+ last;
+ }
+ my $retvalue = $hook->(@_);
+ if (defined($retvalue) && $retvalue eq '0') {
+ $aborted = 1 if (! $aborted);
+ }
+ }
+}
-sub GetGraphData {
- my ($ylab,$r,%GraphDat)=@_;
- my $Col;
- my $data='';
+sub run_statistics {
+ my ($r) = @_;
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 {
- $r->print("Unable to tie hash to db file");
- }
+ &run_hooks('pre',$r,$count);
+ foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
+ last if ($aborted);
+ next if ($seq->{'num_assess'}<1);
+ &run_hooks('pre_seq',$r,$count,$seq);
+ foreach my $res (@{$seq->{'contents'}}) {
+ last if ($aborted);
+ next if ($res->{'type'} ne 'assessment');
+ &run_hooks('pre_res',$r,$count,$seq,$res);
+ foreach my $part (@{$res->{'parts'}}) {
+ last if ($aborted);
+ #
+ # This is where all the work happens
+ my $data = &get_statistics($seq,$res,$part,++$count);
+ &run_hooks('calc',$r,$count,$seq,$res,$part,$data);
+ }
+ &run_hooks('post_res',$r,$count,$seq,$res);
+ }
+ &run_hooks('post_seq',$r,$count,$seq);
}
+ if ($aborted) {
+ &run_hooks('abort',$r);
+ } else {
+ &run_hooks('post',$r,$count);
+ }
+ return;
}
+} # End of %hooks scope
+
+############################################################
+############################################################
1;
__END__