Distance runners are known to have lower pulse rates than their contemporaries. Suppose pulse rates are measured on a random sample of 25 runners 5 minutes after they have completed a 10-kilometer run. The data yield y = 58:2 beats per minute and
s2 = 72.25.
a. Compute the standard error of the average.
b. Use the standard error to set a 95% confidence interval for the mean pulse rate of distance runners.