plotSA: Sigma vs A plot for microarray linear model
Description
Plot log residual standard deviation versus average log expression for a fitted microarray linear model.
Usage
plotSA(fit, xlab="Average log-expression", ylab="log2(sigma)", zero.weights=FALSE, pch=16, cex=0.2, ...)
Arguments
xlab
character string giving label for x-axis
ylab
character string giving label for y-axis
pch
vector or list of plotting characters. Default is integer code 16 which gives a solid circle.
cex
numeric expansion factor for plotting character.
Defaults to 0.2.
zero.weights
logical, should spots with zero or negative weights be plotted?
...
any other arguments are passed to plot
Details
This plot is used to check the mean-variance relationship of the expression data, after fitting a linear model.See points for possible values for pch and cex.
See Also
An overview of diagnostic functions available in LIMMA is given in 09.Diagnostics.