Aren't final grades often "curved", i.e. re-graded according to rank? That would explicitly destroy bimodality, making the final grade distribution consist of non-iid order statistics.
Also, it's commendable that they point out that they expect 5% false positives, but frustrating that they don't go further and explicitly plan for a multiple testing correction procedure. It seems that they don't need it to fail to reject the null "meta-hypothesis", but still.
Also, it's commendable that they point out that they expect 5% false positives, but frustrating that they don't go further and explicitly plan for a multiple testing correction procedure. It seems that they don't need it to fail to reject the null "meta-hypothesis", but still.