7.27 Weight Medics, a clinic in the United Kingdom, offers a weight-loss program for its clients. A review of its records found the following amounts of weight loss, in pounds, for a random sample of 20 clients at the end of a 4-month program:

24 19 5 12 16 10 18 15 8 17 11 6 14 8 19 22 13 20 11 30

a. Find a 95% confidence interval for the population mean.

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.