Bulimia In a study to determine which factors predict who will benefit from treatmen...

Bulimia In a study to determine which factors predict who will benefit from treatment for bulimia nervosa, an article in the British Journal of Clinical Psychology indicates that self-esteem was one of these important predictors.4 The table gives the mean and standard deviation of self-esteem scores prior to treatment, at posttreatment, and during a follow-up:

a. Use a test of hypothesis to determine whether there is sufficient evidence to conclude that the true pretreatment mean is less than 25.

b. Construct a 95% confidence interval for the true posttreatment mean.

c. In Section 10.4, we will introduce small-sample techniques for making inferences about the difference between two population means. Without the formality of a statistical test, what are you willing to conclude about the differences among the three sampled population means represented by the results in the table?