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Item9

Item 9 2 points

Observations are taken on sales of a certain mountain bike in 30 sporting goods stores. The regression model wasY= total sales (thousands of dollars),X₁= display floor space (square meters),X₂= competitors' advertising expenditures (thousands of dollars),X₃= advertised price (dollars per unit).

PredictorCoefficientIntercept1,220.33FloorSpace10.84CompetingAds6.802Price0.1466

(a)Write the fitted regression equation.(Round your coefficientCompetingAdsto 3 decimal places, coefficientPriceto 4 decimal places, and other values to 2 decimal places. Negative values should be indicated by a minus sign.)

y

y^=

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+

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*FloorSpace+

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*CompetingAds+

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*Price

(b-1)The coefficient ofFloorSpacesays that each additional square foot of floor space

• adds about 10.84 to sales (in thousands of dollars).
• takes away 0.1496 from sales (in thousands of dollars).
• takes away 10.84 from sales (in thousands of dollars).
• adds about 6.802 to sales (in thousands of dollars).

(b-2)The coefficient ofCompetingAdssays that each additional $1,000 of"competitors' advertising expenditures"

adds about 6.802 to sales (in thousands of dollars).

(b-3)The coefficient ofPricesays that each additional $1 of advertised price

reduces sales by about 0.1466 from sales (in thousands of dollars).

(c)The intercept is not meaningful, since a mountain bike cannot sell for zero, which will happen if all the variables are zero.

True

(d)Make a prediction forSaleswhenFloorSpace=114,CompetingAds=107, andPrice=1,040.(Enter your answer in thousands. Round your answer to 2 decimal places.)

Sales$

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thousand