aovFbyrow | R Documentation |
Returns on aov F-statistic for each row of x
aovFbyrow(x=matrix(rnorm(1000), ncol=20), cl = factor(rep(1:3, c(7,9,4))))
x |
features by observations matrix |
cl |
factor that classifies the values in each row |
This uses the functions qr()
and qr.qty()
for the main
part of the calculation, for handling the calculations efficently
one F-statistic for each row of x
John Maindonald
See also orderFeatures
mat <- matrix(rnorm(1000), ncol=20)
cl <- factor(rep(1:3, c(7,9,4)))
Fstats <- aovFbyrow(x = mat, cl = cl)
## The function is currently defined as
aovFbyrow <-
function(x=matrix(rnorm(1000), ncol=20),
cl=factor(rep(1:3, c(7,9,4)))){
y <- t(x)
qr.obj <- qr(model.matrix(~cl))
qty.obj <- qr.qty(qr.obj,y)
tab <- table(factor(cl))
dfb <- length(tab)-1
dfw <- sum(tab)-dfb-1
ms.between <- apply(qty.obj[2:(dfb+1), , drop=FALSE]^2, 2, sum)/dfb
ms.within <- apply(qty.obj[-(1:(dfb+1)), , drop=FALSE]^2, 2, sum)/dfw
Fstat <- ms.between/ms.within
}
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