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Question
If `vecx = 18, vecy=100,σy =20` , bary` and correlation coefficient xyr 0.8, find the regression equation of y on x.
Solution
Regression line of y on x is
`y - bary =byx (x - barx)` .........(1)
Now, `byx = (Sigmaxy)/(Sigmax^2) = r((sigmay)/sigma_x)`
`therefore byx =(0,8) (20/14)=16/14 = 8/7`
`therefore(y - bary) = 8/7 (x - barx)` ....(2)
`therefore (y-100)=8/7(x-18)`
`therefore 7y-700 = 8x - 144`
`therefore 7y = 8x +556`
`therefore y = (8/7)x +(556/7)`
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