Question

Great Plains Distributors, Inc. 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.

Sales (000s)		Advertising Dollars (000s)		Number of Accounts		Number of Competitors		Market 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		8		15
177.7		2.9		71		12		17
30.9		8.0		30		12		8
291.9		9.0		56		5		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		6		14
100.2		6.0		40		11		6
135.8		4.0		50		11		8
223.3		7.5		62		9		13
195.0		7.0		59		9		11
73.4		6.7		53		13		5
47.7		6.1		38		13		10
140.7		3.6		43		9		17
93.5		4.2		26		8		3
259.0		4.5		75		8		19
331.2		5.6		71		4		9

Conduct a multiple regression analysis to find the best predictors of sales.

1. Determine the regression equation by omitting the potential variable. (Negative amounts should be indicated by a minus sign. Round the constant value to the nearest whole number and rest of the values to 2 decimal values.)

Sales = ____ + ____ advertising + _______ accounts + ________ competitors

2. Complete the following table. (Negative amounts should be indicated by a minus sign. Leave no cells blank - be certain to enter "0" wherever required. Round your answers to 2 decimal places.)

	Predictor Coefficient SE Coefficient t p-value Constant Advertising Accounts Competitors

3. Determine the regression equation by omitting the advertising variable. (Negative amounts should be indicated by a minus sign. Round your constant value to the nearest whole number and the rest of the values to 2 decimal places.)

Sales = ______ + ______ accounts + _______ competitors

4. Complete the following table. (Leave no cells blank - be certain to enter "0" wherever required. Negative amounts should be indicated by a minus sign. Round your Coef, SE Coef and t-values to 2 decimal places.)

	Predictor Coefficient SE Coefficient t p-value Constant Accounts Competitors

5. Compute the variance inflation factor for the independent variables.

Variance inflation _______

Answer 1