Friday, October 10, 2014

Bulimia Although there are many treatments for bulimia nervosa, some subjects fail to benefit from...

Bulimia Although there are many treatments for bulimia nervosa, some subjects fail to benefit from treatment. In a study to determine which factors predict who will benefit from treatment, 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 post treatment, and during a follow-up:

 

Pretreatment

Post treatment

Follow-up

Sample Mean

20.3

26.6

27.7

Standard Deviation s

5.0

7.4

8.2

Sample Size n

21

21

20

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 post treatment 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?

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