1. With only two predictors
a) The beta weights can be computed as follows:
(1)βY1.2=rY1−rY2r121−r122 \beta_{Y1.2} = \frac{r_{Y1}-r_{Y2}r_{12}}{1-r_{12}^2}\tag{1} βY1.2=1−r122rY1−rY2r12(1)
(2)βY2.1=rY2−rY1r121−r122 \beta_{Y2.1} = \frac{r_{Y2}-r_{Y1}r_{12}}{1-r_{12}^2}\tag{2} βY2.1=1−r122rY2−rY1r12(2)
b) Multiple R can be computed several ways. From the simple correlations, as
(3)RY.12=rY12+rY22−2rY1rY2r121−r122 \textbf{R}_{Y.12} = \sqrt{\frac{r_{Y1}^2+r_{Y2}^2-2r_{Y1}r_{Y2}r_{12}}{1-r_{12}^2}}\tag{3} RY.12=1−r122rY12+rY22−2rY1rY2r12(3)
or from the beta weights and validities as
(4)RY.12=βY1.2rY1βY2.1rY2 \textbf{R}_{Y.12} = \sqrt{\beta_{Y1.2}r_{Y1}\beta_{Y2.1}r_{Y2}}\tag{4} RY.12=βY1.2rY1βY2.1rY2(4)
c) Semipartial correlations in general equal the square root of R2\boldsymbol{R}^2R2 complete minus R2\boldsymbol{R}^2R2 reduced. These are called semipartial correlations because the variance of the other controlled variable(s) is removed from the predictor, but not from the criterion. Therefore, in the two predictor case, they are equal
(5)rY(1.2)2=RY.122−rY22 r_{Y(1.2)}^2 = \textbf{R}_{Y.12}^2 - r_{Y2}^2\tag{5} rY(1.2)2
Multiple and Partial Correlation
最新推荐文章于 2024-08-11 22:44:19 发布