Question: An article in the Sacramento Bee (March 8, 1984, p. A1) reported on a study finding that "men who drank 500 ounces or more of beer a month (about 16 ounces a day) were three times more likely to develop cancer of the rectum than nondrinkers." In other words, the rate of cancer in the beer drinking group was three times that of the non-beer drinkers in this study. What important numerical information is missing from this report?