2

The following table lists the weight of individuals before and after taking a diet prescribed by a weight-loss company for a month:

Weight-loss Data

Individual Weight Before Weight After Weight Loss

A 123.7 123.9 -0.2

B 131.8 131.4 0.4

C 140.0 140 0.0

D 160.5 160.9 -0.4

E 135.8 135.6 0.2

F 163.4 163.4 0.0

You may find thisStudent's t distribution tableuseful in answering the following questions. You may assume that the differences in weight are normally distributed.

a)Calculate the sample standard deviation (s_d) of the changes in individual weights. Give your answer to 2 decimal places.

s_d=

b)A disgruntled customer states:

"This weight-loss company is a complete farce. All the people I know who signed up experienced no changes in their weight at all. I seriously doubt this diet has any effect whatsoever. I want my money back!"

You plan to a hypothesis test on this claim where the hypotheses are:

H₀: the customer's claim is true and the program has no effect on weight

H_A: the customer's claim is not true and the program does have an effect on weight, whether it increases or decreases

According to the data given, you shouldaccept________

the null hypothesis at a confidence level of 90%.