Construct a confidence interval for ud, the mean of the differences d for the population of paired data. Assume that the population of paired differences is normally distributed. 25) 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. Athlete A B C D E F G H Time before training (seconds) 115.2 120.9 108.0 112.4 107.5 119.1 121.3 110.8 122.3 Time after training (seconds) 116.0 119.1 105.1 111.9 109.1 115.2 118.5 110.7 120.9 Construct a 99% confidence interval for the mean difference of the "before" minus "after" times