The Pearson correlation between X₁ and Y is r = 0.40 and SS_Y = 100.When a second variable,X₂,is added to the regression equation,we obtain R² = 0.25.How much additional variability is contributed by adding the second variable as a predictor compared to using X₁ alone? A)9 points B)15 points C)25 points D)40 points

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Quizplus · Accepted Answer

The initial R² with X₁ alone is r² = 0.40² = 0.16. With X₂ added, R² = 0.25. The additional variability is 0.25 - 0.16 = 0.09. Since SS_Y = 100, the additional variability is 0.09 * 100 = 9 points.

The Pearson Correlation Between X1 and Y Is R =

The Pearson Correlation Between X₁ and Y Is R =