Consider the simple linear regression model fit to the weight and blood pressure data in Problem 2.10.

Problem 2.10

The weight and systolic blood pressure of 26 randomly selected males in the age group 25-30 are shown below. Assume that weight and blood pressure (BP) are jointly normally distributed.

a. Construct a normal probability plot of the residuals. Does there seem to be any problem with the normality assumption?

b. Construct and interpret a plot of the residuals versus the predicted response.

c. Suppose that the data were collected in the order shown in the table. Plot the residuals versus time order and comment on the plot.