@craig_story
For legacy quizzes, the Quiz Statistics actually includes two reports. There is the student analysis and the item analysis.
The student analysis includes all of the students, I use that to see who got 0's on their last attempt but did better on a previous attempt. If you are looking at the student analysis and only seeing 8 students out of 40, then something is wrong (well, unless you're using differentiated assignments so only some of them got it). My first quiz had 122 records dues to multiple attempts by the 44 students.
Item analysis is a little harder to figure out, but when I just now generated one and looked at the request that was sent to the server. It was created with a parameter to "includes_all_versions", which means that multiple attempts by students will get used in the analysis.
There used to be an option in the GUI to select whether you wanted all of the versions or just the latest one, but that has been removed from the interface. It's still there on the back end.
The item analysis may seem thin in responses if you're using question groups. For example, this screenshot is from a class of 44 students.
What the 7 in the Answered Student Count means is that 7 students answered that question (from the row), not that 7 students answered the quiz.
