Much like the mean, high and low are displayed per assignment, could the same statistics be made available per each grading group? Often times instructors will split up assignments into different groups with differing weights and these sections are shown at the bottom of student's gradebooks. Can these groups all have their own mean, high and low displayed so students can see how they are doing (per group) compared to the class?
Theoretically a student could go through all of the assignments in each group and individually see their scores compared to the class, but in classes where the amount of assignments is large, this only gives a rough idea of where they stand compared to the class in each group. If the same statistics were made available for each group, students would have a broader idea of how they are doing compared to the class.