aovFbyrow {hddplot} | R Documentation |
Returns on aov F-statistic for each row of x
aovFbyrow(x = Golub, cl = golub.info$cancer)
x |
features by observations matrix |
cl |
fact 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 }