A clinic offers a weight-loss program. The table below gives the amounts of weight loss, in pounds, for a random sample of 20 of its clients at the conclusion of the program. Assume that the data are normally distributed. 11 17 20 10 26 9 13 23 13 18 19 9 15 8 25 21 13 19 13 26

a. Find a 98% confidence interval for the population mean.
(Round to two decimal places)
b. Without doing the calculations, explain whether a 90% confidence interval for the population mean would be wider than, narrower than, or the same as that found in part a