A report published in the International Journal of Obesity claims the "biggie size" fries and lack of exercise aren't the only factors to blame for North America's battle of the bulge. Researchers say some aspects of modern life, including air condition- ing, lack of sleep, and exposure to chemicals, may be making people pudgy. With air conditioning, your body doesn't have to work as hard to keep cool, so it burns fewer calories. The calories you burn just lying in bed doing nothing is called your basal metabolic rate (BMR)-about 70 percent of the calories you burn in a day can be attributed to BMR. To investigate the effect of air conditioning on basal metabolism, eight females from Vancouver who used air conditioning during the hours of night sleep (Group A), and six females who didn't use air conditioning during the hours of night sleep (Group B), were selected and their basal metabolism recorded as shown below.

a. Use the Wilcoxon rank sum test to determine whether the distributions for metabolism measurements are the same for both groups. Use a = 0.05.

b. Use the Wilcoxon rank sum test to determine whether the metabolism measure- ments for Group A are significantly higher than those of Group B. Use a = 0.05.

c. Can you use the normal approximation for the Wilcoxon rank sum test in the above two questions? Why or why not? How about using test? Explain.

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Group A 1150 1088 1090 1027 1150 1145 1199 950 Group B 1086 998 1011 987 1101 1099 1125