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:

Does the position of the arm, when blood pressure is being checked, make any difference? Researchers at the University of California at San Diego, using automated cuffs, took six readings from one hundred emergency room patients whose problems did not involve their circulatory systems. Their blood pressure was measured standing, sitting, and lying down; in each position it was measured with the arm straight out from the body and with the arm held at the side. They found that the position of the arm had a bigger effect on the readings than the position of the body. When the arm was parallel to the body, readings were higher by as much as 14 millimeters of mercury. Dr. David A. Guss, one of the authors of the study, said that no single position was more accurate, “the most important thing is to use a consistent position from measurement to measurement.”

—From the Annals of Internal Medicine, reported in The New York Times, 6 January 2004