Foot ulcers are a common problem for people with diabetes. Higher skin temperatures on the foot indicate an increased risk of ulcers. In a study performed at the Colorado School of Mines, skin temperatures on both feet were measured, in degrees Fahrenheit, for 18 diabetic patients. The results are presented in the following table.

a. Construct a scatterplot of the right foot temperature (y)
versus the left foot temperature (x).

b. Compute the correlation coefficient between the temperatures of the left and right feet.

c. If a patient’s left foot is cooler than the average, would you expect the patient’s right foot to be warmer or cooler than average? Explain.

d. Which of the following is the best interpretation of the correlation coefficient?
i. Some patients have warmer feet than others. Those who have warmer left feet generally have warmer right feet as well.

ii. If we warm a patient’s left foot, the patient’s right foot will become warmer.
iii. If we cool a patient’s left foot, the patient’s right foot will become warmer.

Left Foot Right Foot Left Foot Right Foot 80 80 76 81 85 85 89 86 75 80 87 82 88 86 78 78 89 87 80 81 87 82 87 82 78 78 86 85 88 89 76 80 89 90 88 89