aovFbyrow {hddplot} | R Documentation

## calculate aov F-statistic for each row of a matrix

### Description

Returns on aov F-statistic for each row of `x`

### Usage

    aovFbyrow(x = Golub, cl = golub.info$cancer)

### Arguments

`x` | features by observations matrix
`cl` | fact that classifies the values in each row

### Details

This uses the functions `qr()` and `qr.qty()` for the main part of the calculation, for handling the calculations efficently

### Value

one F-statistic for each row of `x`

### Note

### Author(s)

John Maindonald

### References

### See Also

See also `orderFeatures`

### Examples

    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
      }

[Package hddplot version 0.51 Index]