[R] residuals from lm

[chuck.01]

FYI:
As you are likely thinking:  this doesn't belong here (It just occurred to
me), I am questioning what I did, not the output of lm()
But if someone knows why I am wrong please let me know.



chuck.01 wrote
> 
> Hi, 
> I was playing around with something else and I noticed this matrix code
> for residuals in a linear model doesn't say what lm() says.  Please tell
> me if I am completely misguided here. 
> 
> data(mtcars)
> Y <- as.matrix(mtcars[,1])
> X <- as.matrix(mtcars[,c(2:11)])
> 
> # shouldnt this: 
> H <- X %*% solve(t(X) %*% X) %*% t(X)
> (diag(dim(H)[1]) - H) %*% Y
> 
> # be equal to this:
> residuals(lm(Y~X)) 
> 
> # ???      
> # thanks
> 


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