Great Plains Distributors Incorporated sells roofing and siding products to home improvement retailers, such as Lowe's and Home Depot, and commercial contractors. The owner is interested in studying the effects of several variables on the sales volume of fiber- cement siding products. The company has 26 marketing districts across the United States. In each district, it collected information on the following variables: sales volume (in thousands of dollars), advertising dollars (in thousands), number of active accounts, number of competing brands, and a rating of market potential. Advertising Sales (000s) Dollars (000s) Number of Number of Market Accounts Competitors Potential 79.3 5.5 31 10 8 200.1 2.5 55 8 6 163.2 8.0 67 12 9 200.1 3.0 50 7 16 146.0 3.0 38 B 15 177.7 2.9 71 12 17 30.9 8.0 30 12 8 291.9 9.0 56 10 160.0 4.0 42 8 4 339.4 6.5 73 5 16 159.6 5.5 60 11 7 86.3. 5.0 44 12 12 237.5 6.0 50 6 6 107.2 5.0 39 10 4 155.0 3.5 55 10 4 291.4 8.0 70 14 100.2 6.0 40 6 135.8 4.0 50 223.3 7.5 62 13 195.0 7.0 59 11 73.4 6.7 53 5 47.7 6.1 38 10 140.7 3.6 43 17 93.5 4.2 26 3 259.0 4.5 75 19 331.2 .5.6 71 Conduct a multiple regression analysis to find the best predictors of sales. Click here for the Excel Data File