1. What role does the normal probability plot play in examining whether the multiple regression model is appropriate for a given set of data?
2. Discuss residual analysis in terms of the assump- tions required for using the multiple regression model.
3. Given the printout in Exercise 16.15, briefly summarize the overall results in the context of that exercise:
a. Identify and interpret each of the partial regression coefficients.
b. What proportion of the variation in y is explained by the equation?
c. At what p-value is the overall regression equation significant?
d. For each of the partial regression coefficients, at what p-value does the coefficient differ from zero? Which independent variables appear to be most and least useful in explaining changes in y?