Learn@UW - Changing Question in Quiz after Attempts Have been Made Causes Inaccurate Question Statistics and Details
If you change a question in a quiz after attempts have been made, any subsequent Question Statistics and Question Details displayed for the quiz will be inaccurate. This is because data for the changed questions that should be available for creating Question Statistics and Question Details are erased.
For example, suppose Questions 3 and 4 in a quiz are changed after 10 quiz attempts have been made. After these changes, 15 more quiz attempts are made. If you view the Question Statistics and Question Details, they will show that Questions 3 and 4 have been answered a total of 15 times while the remaining questions have been answered a total of 25 times.
This applies to the data displayed in Question Statistics and Question Details when you select the 'Statistics' icon as well as the data displayed in generated Question Statistics and Question Details reports.
The data for any unchanged questions remain intact.
Adding new or reordering existing quiz questions does not cause any existing data to be erased.
Note that the actual quiz scores are not affected.