Question: The fasting plasma total LDL cholesterol levels (mg/dl) were measured for 60 men aged 45 to 70 years when they entered a cardiovascular rehabilitation program that consisted of a diet and exercise program. A value of <130 mg/dl would be considered normal. At 6 months, their fasting plasma total cholesterol levels were again measured. We can assume that the assumptions have been met.

a) Create a scatter plot to visualize the data and comment on what it is showing you. Use Pearson’s correlation coefficient to determine if a relationship exists between cholesterol levels at the two measurement times. State the appropriate hypotheses. Assume all assumptions are met. Use a scatter plot to help you interpret the data.

b) Calculate a least-squares regression line for the above data.

c) Use the relationship between the men’s initial and post follow-up total LDL cholesterol levels to predict the most likely follow-up total cholesterol level for a 65 year old man who has a baseline total cholesterol level of:

i) 150

ii) 172

d) Please comment on what you would report back to the men who participated in this rehabilitation program about your results. Also comment on the variables that could provide an explanation for your findings.