The coefficient of correlation is r between X and Y having standard deviation $$\sigma_x$$ and $$\sigma_y$$ . The tangent of the angle

between two lines of regression is:

A

$$\frac{1 - r^2}{r}$$

B

$$\frac{1 - r^2}{r} \sigma_X \sigma_Y$$

C

$$\frac{1 - r^2}{r} \frac{\sigma_X \sigma_Y}{\sigma_X + \sigma_Y}$$

D

$$\frac{1 - r^2}{r} \frac{\sigma_X \sigma_Y}{\sigma^2_X + \sigma^2_Y}$$