Use your calculator to answer the following:

A coach uses a new technique in training middle distance runners. The times for 9 different athletes to run 800 meters before and after this training are shown below.

Assume that the conditions and assumptions for inference are satisfied.

Athlete: A B C D E F G H I

Time Before: 115.2 120.9 106.0 112.4 107.5 119.1 121.3 110.8 122.3

Time After: 116.0 119.1 105.1 111.9 109.1 115.2 118.5 110.7 120.9

a) Do the data suggest that there is a significant difference between the "before" and "after" times? Perform the appropriate test at the significance level 1%. Clearly state your conclusions.

I'm not sure what test to use would this be a 2-propZtest? or 2-sampTtest?

b) Construct a 99% confidence interval for the mean difference between the "before" and "after" times.