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Question
If n = 5, Σx = Σy = 20, Σx2 = Σy2 = 90, Σxy = 76 Find the regression equation of x on y
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Solution
Given, Σx = 20, Σy = 20, Σx2 = 90, Σy2 = 90, Σxy = 76, n = 5
Now,
`barx = (sumx)/"n" = 20/5` = 4
`bary = (sumy)/"n" = 20/5` = 4
bxy = `(sumxy - "n" bar(x) bar(y))/(sum y^2 - "" bar(y)^2`
= `(76 - 5 xx 4 xx 4)/(90 - 5(4)^2`
= `(76 - 80)/(90 - 80)`
= – 0.4
The regression equation of X on Y is given by `("X" - barx) = "b"_(xy) ("Y" - bary)`
∴ (X – 4) = – 0.4(Y – 4)
∴ X + 0.4Y = 5.6
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