If n = 5, Σx = Σy = 20, Σx2 = Σy2 = 90 , Σxy = 76 Find Covariance (x,y) - Mathematics and Statistics

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Sum

If n = 5, Σx = Σy = 20, Σx2 = Σy2 = 90 , Σxy = 76 Find Covariance (x,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

cov(X, Y) = `1/"n" sumxy - bar(x)  bar(y)`

= `1/5 xx 76 - 4 xx 4`

= 15.2 – 16

= – 0.8

Concept: Properties of Regression Coefficients
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Chapter 2.3: Linear Regression - Q.4

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