Question: Gotta love your Stairmaster

Both employers and insurers are on the lookout for ways to control the costs of health insurance. Toward that end, an insurer-led study of workers in the financial services industry concerns the average fat loss between those who only diet, and those who only exercise. Following are the sample results from study participants on the amount of fat lost after one year:

Group 1: Diet Only

Sample mean: 5.9 kg

Sample standard deviation: 4.1 kg

Level of significance: .05

Number of participants: 42

Group 2: Exercise Only

Sample mean: 4.1 kg

Sample standard deviation: 3.7 kg

Level of significance: .05

Number of participants: 47

Research question: Is there a significant difference in average fat lost between these two methods?

a. Determine the null and alternate hypotheses.

b. Calculate the appropriate test statistic.

c. Find the p-value.

d. What do you conclude? Be specific.