Analyze each of the following investigations, or arguments, and indicate which of the methods of causal reasoning—Mill’s methods—are being used in each of them:

A 16-year study followed 8,867 non-smoking male professionals with normal body weight who participated in vigorous daily exercise and ate a healthy diet. Those who drank one-half to two normal servings of wine, beer, or hard liquor a day had a 41 to 62 percent reduction of heart attack risk compared with those who drank no alcohol at all. It seems clear that in moderate quantities alcoholic drinks reduce the  likelihood of heart attack. This effect is found not only in those with heart disease. The lead author of the study writes: “Even in the lowest risk people, we still fi nd a lower risk associated with moderate drinking.”
—Kenneth Mukamal, “Alcohol Consumption and Risk for Coronary Heart Disease in Men with Healthy Lifestyles,” Archives of Internal Medicine, 23 October 2006