Weight loss: In a study to determine whether counseling could help people lose weight, a sample of people experienced a group-based behavioral intervention, which involved weekly meetings with a trained interventionist for a period of six months. The following data are the numbers of pounds lost for

14

people. Assume the population is approximately normal. Perform a hypothesis test to determine whether the mean weight loss is less than

20

pounds. Use the

=0.10

level of significance and the

P

-value method with the TI-84 Plus calculator