hi there i am having a hard time figuring this question out. (this is a biostatistics question)

Exercise 1 1 .6. 16 professional marathon runners participated in a pro- 3-month training program that included one hour of swimming 1 three times a week. The best personal time (MTP) in minutes for the 5 km race of these athletes was recorded, before and after the training program. The data are summarized in the table following : MTP before MTP after Difference \"1 = X - yi_ Average 1,7 Standard deviation 1:6 Using this data, can we say that the integration of swimming in the training program of professional runners improves their MTP? Use an a-Ievel hypothesis test = 0.005. Assume that the variables X, Y and D are distributed normally and that the variables X and Y have the same variances