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 variance is predicted by adding the second variable compared to using X₁ alone? A)9 points B)15 points C)25 points D)40 points

Question

Quizplus · Accepted Answer

The additional variance predicted by adding X2 is calculated by the difference in R² values: R² with both variables - R² with X1 alone. R² with X1 alone is r² = 0.40² = 0.16. The additional variance is 0.25 - 0.16 = 0.09, which is 9 points.

The Pearson Correlation Between X1 and Y Is R =

The Pearson Correlation Between X₁ and Y Is R =