The lines of regression of bivariate population are 8x-10y+66=0 and 40x-18y = 214. The variance of x is 9.

Find,

a. coefficient of correlation r

b. the standard deviation y

Given

$\begin{align} 8x-10y+66 &=0 \\ 8x-10y & =-66 - - - -1 \\ 40x-18y& = 214 - - - - 2 \\ \sigma x& = 9\\ \end{align}$

To find x&y solve equation 1 & 2, simultaneously, we get,

x=13

y=17

To find r: Suppose, the first equation represent the line …