How to report on correctness of survey responses?

System

I was thinking to either add correct answer to the 'question' object, or have person who creates test to enter correct answers as first participant, then use report to compare that set of answers to all the others. Any ideas on this? Any better approaches?

Ideal report or query might be:
* Header: test | user | duration taken
* Detail: user | question | answer | correct Y/N
* Footer: user | test score (count correct=Y) | "out of"

Fundamental question: where are all the answers per trustee stored? I can only see the individual's text answers, but seems multi-choice answers are stored only as an aggregate?