Question

The two regression lines are $2x - 9y + 6 = 0$ and$x - 2y + 1 = 0$. What is the correlation coefficient between x and y

• A. –2/3
• B. 2/3
• C. 4/9
• D. None of these

Answer 1

Answer: (B)

2/3

Answer 2

Given regression lines are, 2x – 9y + 6 = 0

and $x - 2y + 1 = 0$

∴ $b_{yx} =$Slope of line of regression of y on x ⇒ $b_{xy} = \frac{2}{9}$.

$\frac{1}{b_{xy}}$ = Slope of line of regression of x on y $= \frac{1}{2}$

$\Rightarrow$ $b_{xy} = 2.$

Hence, $r^{2}$ = $b_{yx}.b_{xy}$ ⇒ $r = + \frac{2}{3}$.