=+26. Cereal nutrition. Breakfast cereal manufacturers publish nutrition information on each box of their product. As we saw in Chapter 16, there is a long history of cereals being associated with nutrition. Here’s a regression to predict the number of Calories in breakfast cereals from their Sodium, Potassium, and Sugar content, and some diagnostic plots.

Dependent variable is: Calories R-squared = 38.4% R-squared (adjusted) = 35.9%

s = 15.60 with 77 - 4 = 73 degrees of freedom Variable Coeff SE(Coeff) t-ratio P-value Intercept 83.0469 5.198 16.0 60.0001 Sodium 0.057211 0.0215 2.67 0.0094 Potassium -0.019328 0.0251 -0.769 0.4441 Sugar 2.38757 0.4066 5.87 60.0001

–1.25 0.00 1.25 Nscores Leverages 0.16 0.12 0.08 0.04

– 2.8 Studentized Residuals

– 0.8 1.2 20 15 10 5

–0 100 200 300 Potassium Residuals 20 0

–20 The shaded part of the histogram corresponds to the two cereals plotted with x’s in the normal probability plot of the leverages and the residuals plot. These are All-Bran with Extra Fiber and All-Bran.