Chapter 18, Problem 38E

Marathon start-up years 2016 When we considered the Boston Marathon in Exercise 37, we were unable to check the Nearly Normal Condition. Here’s a histogram of the differences:

The three largest differences are in the first three years of wheelchair competition: 1977, 1978, and 1979. Often the start-up years of new events are different; later on, more athletes train and compete. If we omit those three years, the summary statistics change as follows:

Summary of wheelchrF – runM

n = 37

Mean = –15.29

SD = 18.14

1. a) Comment on the assumptions and conditions.
2. b) Assuming that these times are representative of such races, construct and interpret a 95% confidence interval for the mean difference in finishing time.
3. c) Would a hypothesis test at a = 0.05 reject the null hypothesis of no difference? What conclusion would you draw?