Index: lib/grade/grade_category.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/grade/grade_category.php,v
retrieving revision 1.96.2.4
diff -u -r1.96.2.4 grade_category.php
--- lib/grade/grade_category.php	1 Nov 2007 08:50:33 -0000	1.96.2.4
+++ lib/grade/grade_category.php	13 Nov 2007 00:20:23 -0000
@@ -201,7 +201,7 @@
 
         $this->apply_forced_settings();
 
-		// these are exclusive
+                // these are exclusive
         if ($this->droplow > 0) {
             $this->keephigh = 0;
         } else if ($this->keephigh > 0) {
@@ -612,8 +612,8 @@
                     if ($items[$itemid]->aggregationcoef <= 0) {
                         continue;
                     }
-                    $weightsum += $items[$itemid]->aggregationcoef;
-                    $sum       += $items[$itemid]->aggregationcoef * $grade_value;
+                    $weightsum += $items[$itemid]->aggregationcoef*$items[$itemid]->grademax;
+                    $sum       += $items[$itemid]->aggregationcoef * $grade_value*$items[$itemid]->grademax;
                 }
                 if ($weightsum == 0) {
                     $agg_grade = null;
@@ -642,9 +642,17 @@
 
             case GRADE_AGGREGATE_MEAN:    // Arithmetic average of all grade items (if ungraded aggregated, NULL counted as minimum)
             default:
-                $num = count($grade_values);
-                $sum = array_sum($grade_values);
-                $agg_grade = $sum / $num;
+                $weightsum = 0;
+                $sum       = 0;
+                foreach($grade_values as $itemid=>$grade_value) {
+                    $weightsum += $items[$itemid]->grademax;
+                    $sum       += $grade_value*$items[$itemid]->grademax;
+                }
+                if ($weightsum == 0) {
+                    $agg_grade = null;
+                } else {
+                    $agg_grade = $sum / $weightsum;
+                }
                 break;
         }