Swim the lake 2006:
People swam across Lake Ontario 42 times between 1974 and 2006 (www.soloswims.com). We might be interested in whether they are getting any faster or slower. Here are the regression of the crossing Times (minutes) against the Year of the crossing and the residuals plot:
a) What does the mean for this regression?
b) Are the swimmers getting faster or slower? Explain.
c) The outlier seen in the residuals plot is a crossing by Vicki Keith in 1987 in which she swam a round trip, North to South and then back again. Clearly, this swim doesn't belong with the others. Do you think that removing it would change the model a lot? Explain.