A national chain of health clubs says the mean amount of weight lost by members during the past month was at least 5 pounds. Skeptical of this claim, a consumer advocate believes the chain's assertion is an exaggeration.
She interviews a random sample of 40 members, finding their mean weight loss to be 4.6 pounds, with a standard deviation of 1.5 pounds. At the 0.01 level of significance, evaluate the health club's contention.