People gain weight when they take in more energy from food than they expend. A Mayo Clinic study investigated the link between obesity and energy spent on daily activities. They chose healthy volunteers, none of whom exercised on a regular basis. Ten of the subjects were lean, and ten were mildly obese (heavy). They attached sensors to monitor the subjects' movements for ten days. The time (in minutes per day) spent standing or walking for each subject is provided in the Excel spreadsheet. (10 points)
a) State your null and alternative hypotheses.
b) Calculate the mean and standard deviation for each group.
c) Compare the two group means and test your hypothesis. State your conclusion in terms of the hypothesis and report the associated probability.
d) Compute the confidence interval for the difference between the two sample means.