This document describes how to handle the problem if you receive an Internal Server Error when attempting to view the statistics for a quiz.
If you attempt to view the statistics for a quiz by selecting Statistics from the drop-down by a quiz and one or more students have a null overall attempt score, an Internal Server (HTML 500) Error is triggered.
This is a known issue.
It is unusual but possible for the scores for a quiz attempt that has been submitted to contain null data.
If the problem occurs, the instructor should select Grade from the drop-down by the quiz and look for null scores.
Grading the quiz attempts manually for attempts with null scores so they contain actual quiz scores resolves the problem. The quiz statistics can then be viewed.