CGPET 2014 Solved Paper

Let the line of regression of y on x be
3x+12y=19
or ‌‌y=‌

−3x+19

12

and x on y be
x=‌

−3y+46

9

∴ Regression coefficient of y on x is
byx‌=‌

−3

12

‌=−‌

1

4

and regression coefficient of x on y is
bxy‌=−‌

3

9

=−‌

1

3

∴‌ Correlation ‌rxy‌=−√byx×bxy
(here, we take negative sign outside the square root, because both regression coefficients are negative)
‌=−√−‌

1

4

×−‌

1

3

‌=−√‌

1

12

‌=−√0.083=−0.289