Refer to the weight loss data on 588 cancer patients and 600 healthy controls (WGTLOSS). Weight loss among cancer patients is a well-known phenomenon. Of interest to clinicians is the role played in the process by metabolic abnormalities. One investigation into the relationships among these variables yielded data on whole-body protein turnover (Y) and percentage of ideal body weight for height (X). Subjects were lung cancer patients and healthy controls of the same age. Select a simple random sample of size 15 from each group and do the following:

(a) Draw a scatter diagram of the sample data using different symbols for each of the two groups.

(b) Use dummy variable coding to analyze these data.

(c) Plot the two regression lines on the scatter diagram. May one conclude that the two sampled populations differ with respect to mean protein turnover when percentage of ideal weight is taken into account?

May one conclude that there is interaction between health status and percentage of ideal body weight?

Prepare a verbal interpretation of the results of your analysis and compare your results with those of your classmates.