Question

From the equation of the two regression lines, $4x+3y+7=0$ and $3x+4y+8=0$, find: Coefficient of correlation.

Answer 1

Coefficient of correlation $|r|=\sqrt{b_{yx}.b_{xy}}=\sqrt{\frac{-3}{4}\times \frac{-3}{4}}$
$\Rightarrow r=\pm \frac{3}{4}$
But r has the same sign as regression coefficients.
$\therefore r=\frac{-3}{4}$