1.1. The cumulative frequency graphs show information about the times taken by 100 male runners and by 100 female runners to finish the London marathon. 

A male runner is chosen at random.

Find an estimate for the probability that this runner took less than 4 hours to finish the London marathon.

1.2. Use medians and interquartile ranges to compare the distribution of the times taken by the male runners with the distribution of the times taken by the female runners.