CPM Homework Help : ACC6 Problem 8-39

Assume that the histograms below represent the amount of time it took two different groups of $100$ people to run a $5$ K race. Assume that the mean of each histogram is the same. Which group has a greater mean absolute deviation? Why?

A histogram with 9 bars, with the following heights: 7, 8, 9, 7, 5, 8, 10, 8, 5.
Group A

A histogram with 9 bars, with the following heights: 5, 6, 7, 9, 10, 8, 7, 6, 5.
Group B

Hint:

Group B has more data points near the center. Group A has more data points farther from the center.