Use the results from Problems 2 and 4 for the following:

(a) Compute and interpret R2.

(b) Plot the residuals against fat content.

(c) Based on the residual plot drawn in part (b), is a linear model appropriate for describing the relation between fat content and calories?

(d) Are there any outliers or influential observations?

(e) Suppose a White Castle cheeseburger (affectionately known as a slider) is added to the data set. Sliders have 9 grams of fat and 80 calories. Is this observation an outlier or influential?