Suppose you, as the manager of boston bbq, decide you would like to include more than just number of customers to predict sales of pork sandwiches. You decide to add number of discount coupons for pork sandwiches handed out in the previous week and an indicator for stores in low, middle, and high income areas as variables. You also increase the number of observations to 30 stores. 

Your data gives you the following output: 






a) What is the estimated regression equation? 



b) Why is there no dummy variable for “High Income Areas” as there is with middle and low? 



c) Is the overall model significant at the α = .01 level? How can you tell? 


d) Are each of the coefficients significant at the α = .05 level? How can you tell (explain whether or not each coefficient is significant)? 


e) How much of the variation in y is explained by our regression? 



f) How many sandwiches do we predict will be sold if a store is in a middle income area, handed out 1500 coupons in the previous week, and has 464 customers?