Problem description: Instructor receives a 500 Error when attempting to view statistics for a Quiz.
Solution: Check to see whether any student has a quiz attempt that is ungraded.
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An ungraded Quiz will cause the 500 Error because D2L cannot calculate statistics when any attempt has a "null" score -- an absence of a grade. (The null score can be caused by an interruption occurring while a quiz is being submitted, for example, losing network connectivity. )
To grade the ungraded Quiz attempt, follow these steps:
Quiz Stats should now be available without the 500 Error.