Boston startup years 2007. When we considered the Boston Marathon in Exercise 15, we were unable to check the Nearly Normal Condition. Here's a histogram of the differences:
Those three large differences are 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 wheelchair = runM
N = 28
Mean =-12.1780
SD = 19.5116