Anutritionist is interested in whether two proposed diets, diet 1 and diet 2, work equally well in providing weight-loss for customers. in order to assess a difference between the two diets, she puts 50 customers on diet 1 and 60 other customers on diet 2 for two weeks. those on diet 1 had weight losses with an average of 11 pounds and a standard deviation of 3 pounds, while those on the latter lost an average of 8 pounds with a standard deviation of 2 pounds. do the diets differ in terms of their weight loss? (alpha 0.05)