The histogram of marathon times includes data for men and women and also for both an Olympic marathon and an amateur marathon. Greater values indicate slower runners.

a. Describe the shape of the distribution.
b. What are two different possible reasons for the two modes?
c. Knowing that there are usually fewer women who run marathons than men, and that more people ran in the amateur marathon than in the Olympic marathon, look at the size of the mounds and try to decide which of the reasons stated in part b is likely to cause this. Explain.

90 80 70 60 50 40 30 20 10 8000 12000 16000 20000 Times for Two Marathons (seconds)