Data Set 3: Two sets of 50 people ran a mile. They first ran a mile without any conditioning/training. They then ran a mile a week later. Their times, in seconds, are recorded as follows: a column for the first time and a column for the second time. The people in the first set did no training/conditioning between the first time they ran a mile and the second time they ran a mile; the second group participated in a week-long conditioning program and then ran their second mile time. Your task is to test the claim that the mean of the differences in people who did conditioning is less than 0 (that their mile time DECREASED, i.e. got faster). Compute an appropriate 95% confidence interval for the mean difference between try 1 and try 2 for those who participated in the conditioning.