Q.From the following data with usual notations find correlation coefficient between X and Y:
$n = 50$, $\sum (x_i - \bar{x})(y_i - \bar{y}) = 420$, $\sigma_x = 4$, $\sigma_y = 3$.

The correlation coefficient is the signed geometric mean of the regression coefficients, $r=\pm\sqrt{b_{yx}\cdot b_{xy}}$, with the common sign of the coefficients; conversely $b_{yx}=r\dfrac{\sigma_y}{\sigma_x}$ and $b_{xy}=r\dfrac{\sigma_x}{\sigma_y}$. Substitute into the appropriate line to estimate a value. Because both lines m …