improve stats handling

templates/exam_stats.html

@@ -0,0 +1,20 @@
+{% extends 'base.html' %}
+
+{% block content %}
+    <h2>{{exam.name}}</h2>
+
+
+    {% if exam.stats_candidates < 4 %}
+        Not enough data points...
+    {% else %}
+
+        <div id="stats-plot">{{exam.stats_graph|safe}}</div>
+
+        Questions: <span id="question-number">{{question_number}}</span><br />
+        Available marks: {{exam_stats_max_possible}}<br />
+        Mean: {{exam.stats_mean}}, Median {{exam.stats_median}}, Mode {{exam.stats_mode}}<br />
+        Top score: {{exam.stats_max}}
+
+        <p class="small-gray">Note: scores < 10% of the total score are excluded from these statistics
+    {% endif %}
+{% endblock %}