Question

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Reported magazine newsstand sales were used to predict audited sales for 10 magazines. For that data, SSR = 132,184.22 and SST = 144,410.99. Complete parts (a) through (c). a. Determine the coefficient of determination, r?, and interpret its meaning. 2 (Round to four decimal places as needed.) Interpret the meaning of r2. It means that % of the variation in audited newsstand sales (Round to two decimal places as needed.) be explained by the variation in reported newsstand sales. b. Determine the standard error the estimate. Syx (Round to four decimal places as needed.) c. How useful do you think this regression model is for predicting audited sales? A. It is very useful for predicting audited sales because the coefficient of determination is close to 1 and the standard error of the estimate is fairly small. B. It is not very useful for predicting audited sales because although the coefficient of determination is close to 1, the standard error of the estimate is fairly small. C. It is not very useful for predicting audited sales because the coefficient of determination is close to 0 and the standard error of the estimate is fairly large. D. It is very useful for predicting audited sales because the coefficient of determination is close to 1. The standard error of the estimate does not indicate whether a regression model is useful.

Answer 1

Solution:

n = 10 , SSR = 132,184.22 , SST = 144,410.99 , SSE = SST - SSR = 144,410.99-132,184.22 = 12226.77

r^2 = SSR/SST = 132,184.22/144,410.99 = 0.9153

a.

r^2 = 0.9153

It means that 91.53 % of the variation in audited newsstand sales is be explained by the variation in reported newsstand sales.

b.

Sxy = √SSE/n-2 = √12226.77/8 = 39.0941

Sxy = 39.0941

c.

• A. It is very useful for predicting audited sales because the coefficient of determination is close to 1 and the standard error of estimate is fairly small.