You are trying to determine the effects of three packaging displays (A, B, and C) on sales of toothpaste.

The file P16_59.xlsx contains the number of cases of toothpaste sold for nine consecutive weeks. The type of store (GR
grocery, DI
discount, and DE

department store) and the store location (U
urban, S
suburban, and R
rural) are also listed.

a. Run a multiple regression to determine how the type of store, display, and store location influence sales. Which potential explanatory variables should be included in the equation? Be sure to explain your rationale for including or excluding variables.

b. What type of store, store location, and display appears to maximize sales?