Plasma-glucose levels are used to determine the presence of diabetes. Suppose the mean ln (plasma-glucose) concentration(mg/dL) in 35- to 44-year-olds is 4.86 with standard deviation = 0.54. A study of sedentary people is planned to test whether they have a different, i. e., a two-tailed test, level of plasma-glucose than the general population. The study will test significance at the 0.05 level. One study indicated that that the mean for the sedentary group will be about 4.96 mg/dL. How many sedentary people are needed in the study to achieve 80% power?