This exercise requires the use of a computer package. The accompanying data resulted from a study of the relationship between y brightness of finished paper and the independent variables x1 hydrogen peroxide (%

by weight), x2 sodium hydroxide (% by weight), x3 silicate (% by weight), and x4 process temperature

(“Advantages of CE-HDP Bleaching for High Brightness Kraft Pulp Production,” TAPPI [1964]: 107A–173A).

a. Find the estimated regression equation for the model that includes all independent variables, all quadratic terms, and all interaction terms.

b. Using a .05 significance level, perform the model utility test.

c. Interpret the values of the following quantities:
SSResid, R2 , and se.