a. Suppose that several high-profile technology businesses move their corporate headquarters to locations near a mall, boosting incomes in that area by $5,000. If the collection of retailers in the...

a. Suppose that several high-profile technology businesses move their corporate headquarters to locations near a mall, boosting incomes in that area by $5,000. If the collection of retailers in the mall remains the same, how much would you expect sales to increase at an outlet of the type considered in the preceding discussion? Should you use the marginal or partial slope for income?₅

b. A contractor replaces windows and siding in suburban homes. The homes vary in size; repairs to larger homes usually require more windows and siding. He fits two regressions: a simple regression of material costs on the number of windows and a multiple regression of material costs on the number of windows and the number of square feet of siding. Which should be larger: the marginal slope for the number of windows or the partial slope for the number of windows?₆