Interpreting the multiple regression analysis for the given MINITAB output
The district manager of Jasons, a large discount electronics chain, is investigating why certain stores in her region are performing better than others. She believes that 3 factors are related to total sales: the number of competitors in the region, the population in the surrounding area, and amount spent on advertising. From her district, consisting of several hundred stores, she selects a random sample of 30 stores. For each store she gathered the following information.
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Y =
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total sales last year (in $ thousands).
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X1 =
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number of competitors in the region.
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X2 =
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population of the region (in millions).
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X3 =
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advertising expense (in $ thousands).
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The sample data were run on MINITAB, with the following results.
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Analysis of variance
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SOURCE
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DF
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SS
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MS
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Regression
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3
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3050.00
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1016.67
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Error
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26
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2200.00
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84.62
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Total
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29
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5250.00
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Â
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Predictor
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Coef
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StDev
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t-ratio
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Constant
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14.00
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7.00
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2.00
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X 1
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-1.00
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0.70
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-1.43
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X 2
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30.00
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5.20
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5.77
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X 3
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0.20
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0.08
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a) What are the estimated sales for the Bryne store, which has 4 competitors, a regional population of 0.4 (400,000), and advertising expense of 30 ($30,000)?
b) Calculate the R2 value.
c) Calculate the multiple standard error of estimate.