Refer to Exercise 9.80.
a. Construct a 99% confidence interval for the difference in the average number of meters swum by breaststroke versus individual medley swimmers.
b. How much longer do pure breaststroke swimmers practice that stroke than individual medley swimmers? What is the practical reason for this difference?
Exercise 9.80.
How much training time does it take to become a world-class breaststroke swimmer? A survey published in The American Journal of Sports Medicine reported the number of meters per week swum by two groups of swimmers-those who competed only in breaststroke and those who competed in the individual medley (which includes breaststroke). The number of meters per week practicing the breaststroke swim was recorded and the summary statistics are shown below.

Is there sufficient evidence to indicate a difference in the average number of meters swum by these two groups of swimmers? Test using α = .01.

Breaststroke Individual Medley Sample Size Sample Mean Sample Standard Deviation7162 130 9017 80 5853 1961