--- loncom/interface/statistics/lonproblemanalysis.pm	2006/08/17 21:19:47	1.127
+++ loncom/interface/statistics/lonproblemanalysis.pm	2008/10/23 09:07:51	1.131
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonproblemanalysis.pm,v 1.127 2006/08/17 21:19:47 raeburn Exp $
+# $Id: lonproblemanalysis.pm,v 1.131 2008/10/23 09:07:51 bisitz Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -144,25 +144,27 @@ sub BuildProblemAnalysisPage {
                 $r->print(&Apache::lonstathelpers::render_resource($resource));
             }
             $r->rflush();
-            my %Data = &Apache::lonstathelpers::get_problem_data
-                ($resource->src);
-            my $problem_data = $Data{$current_problem->{'part'}.
-                                    '.'.
-                                    $current_problem->{'respid'}};
-            if ($current_problem->{'resptype'} eq 'option') {
-                &OptionResponseAnalysis($r,$current_problem,
-                                        $problem_data,
-                                        \@Students);
-            } elsif ($current_problem->{'resptype'} eq 'radiobutton') {
-                &radio_response_analysis($r,$current_problem,
-                                         $problem_data,
-                                         \@Students);
-            } elsif ($current_problem->{'resptype'} eq 'numerical') {
-                &numerical_response_analysis($r,$current_problem,
-                                             $problem_data,\@Students);
-            } else {
-                $r->print('<h2>Analysis of '.$current_problem->{'resptype'}.' is not supported</h2>');
-            }
+	    if (@Students) {
+		my %Data = &Apache::lonstathelpers::get_problem_data
+		    ($resource->src);
+		my $problem_data = $Data{$current_problem->{'part'}.
+					     '.'.
+					     $current_problem->{'respid'}};
+		if ($current_problem->{'resptype'} eq 'option') {
+		    &OptionResponseAnalysis($r,$current_problem,
+					    $problem_data,
+					    \@Students);
+		} elsif ($current_problem->{'resptype'} eq 'radiobutton') {
+		    &radio_response_analysis($r,$current_problem,
+					     $problem_data,
+					     \@Students);
+		} elsif ($current_problem->{'resptype'} eq 'numerical') {
+		    &numerical_response_analysis($r,$current_problem,
+						 $problem_data,\@Students);
+		} else {
+		    $r->print('<h2>Analysis of '.$current_problem->{'resptype'}.' is not supported</h2>');
+		}
+	    }
         }
         $r->print('<hr />');
     } else {
@@ -327,11 +329,14 @@ sub numerical_plot_percent {
             last;
         }
     }
+    $percent_spread = $highest_percent - $lowest_percent;
     my $bin_size = 1;
     foreach (qw/0.01 0.05 0.1 0.5 1 2 5 10 20 25 50 100/) {
         if ($lowest_percent/2 < $_){
             $bin_size = $_;
-            last;
+	    if ( ($percent_spread/$bin_size) < $max_bins ) {
+		last;
+	    }
         }
     }
     my @bins;
@@ -406,6 +411,10 @@ sub numerical_plot_differences {
     } elsif ($low_bin < 0 && $high_bin < -$low_bin) {
         $high_bin = -$low_bin;
     }
+    if ($high_bin == $low_bin) {
+	$high_bin+=1;
+	$low_bin-=1;
+    }
     if (!$min_bin_size ||
         ($high_bin -$low_bin)/$min_bin_size * 2 > $max_bins) {
         $min_bin_size = abs($high_bin - $low_bin) / $max_bins * 2;
@@ -627,11 +636,21 @@ sub numerical_determine_answers {
                                                                 $sdom);
         # make the key
         my $key = $partid.'.'.$respid;
+	# pick one of the possible answers
+	my $which = 'INTERNAL';
+	if (!exists($analysis->{$key}{$which})) {
+	    $which = (sort(keys(%{ $analysis->{$key} })))[0];
+	}
         foreach my $item ('answer','unit','ans_high','ans_low') {
-            $correct->{$sname.':'.$sdom}->{$item} = 
-                $analysis->{$key.'.'.$item}->[0];
+	    if (ref($analysis->{$key.'.'.$item}) eq 'ARRAY') {
+		$correct->{$sname.':'.$sdom}->{$item} = 
+		    $analysis->{$key.'.'.$item}[0];
+	    } else {
+		$correct->{$sname.':'.$sdom}->{$item} = 
+		    $analysis->{$key.'.'.$item}{$which}[0][0];
+	    }
         }
-        $answers{$analysis->{$key.'.answer'}->[0]}++;
+        $answers{$correct->{$sname.':'.$sdom}{'answer'}}++;
         &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,
                                                  &mt('last student'));
     }
@@ -1835,7 +1854,7 @@ sub CreateInterface {
     $Str .= '<tr>';
     $Str .= '<td align="center"><b>'.&mt('Sections').'</b></td>';
     $Str .= '<td align="center"><b>'.&mt('Groups').'</b></td>';
-    $Str .= '<td align="center"><b>'.&mt('Enrollment Status').'</b></td>';
+    $Str .= '<td align="center"><b>'.&mt('Access Status').'</b></td>';
     $Str .= '<td align="center">&nbsp;</td>';
     $Str .= '</tr>'."\n";
     ##
@@ -1899,11 +1918,11 @@ sub CreateInterface {
     $Str .= '<nobr><label>'.&mt('Number of Plots [_1]',$numplots_selector).
         '</label></nobr>';
     ##
-    $Str .= '<nobr><label>'.&mt('Status: [_1]',
-                                 '<input type="text" '.
-                                 'name="stats_status" size="60" value="" />'
-                                 ).
-                    '</label></nobr>';
+    $Str .= '<span class="LC_nobreak"><label>'
+           .&mt('Status: [_1]',
+                    '<input type="text" name="stats_status"'
+                   .' size="60" value="" readonly="readonly" />')
+           .'</label></span>';
     $Str .= '</td>';
     ##
     ##