1. The weights of boxes of Naturola Cornflakes are supposed to vary with a mean of 9 oz. and standard deviation 2 oz. Each hour, a random sample of 60 boxes is selected from the production line. One day an incompetent technician resets the box-filling machine, and afterwards one of the hourly samples has a mean weight of 9.74 and standard deviation 2.1.

2. According to a recent report on National Public Radio (NPR), a company that makes an anthrax detector for the Post Office is trying to determine the false-positive rate, i.e., the proportion of anthrax-free letters for which the device will sound an alarm. In order to be economical for the Post Office, the false-positive rate needs to be less than 4%. Suppose 367 anthrax-free letters are run through the detector and the alarm sounds for 23 of them.

3. An experiment was conducted to compare people’s reaction times to red light versus green light. The reaction times (in seconds) for subjects exposed to different colored light, were as follows:

4. An article in last year’s New England Journal of Medicine concerns the risk of sudden death due to heart attack during or shortly after vigorous exertion. In a sample of 8,414 male physicians who exercised on a regular basis there were 144 such deaths, whereas in a sample of 7557 male physicians who did not exercise regularly there were 176 deaths.