xyellipse

DESCRIPTION:

Scatter Plot with Overlaid Ellipse(s)

USAGE:

xyellipse(x, variables=c(1, 2), plot.data=T, confidence=0.95)

REQUIRED ARGUMENTS:

x
a cov, covRob, or fit.models (containing only cov and covRob elements) object.

OPTIONAL ARGUMENTS:

variables
when the dimension of the covarianvce matrix is greater than 2 this argument is used to specify which pair of variables to plot. It can be either a character vector containing two names or a numeric vector containing two column indicies.
plot.data
a logical flag, if TRUE a scatter plot of the data is added to the plot.
confidence
the fraction of the density inside the ellipse.

SIDE EFFECTS:

A plot is produced on a graphics device.

EXAMPLES:

stack.fm <- fit.models(list(Robust="covRob", Classical="cov"),
     data=stack.dat)
xyellipse(stack.fm, variables = c("Air.Flow", "Acid.Conc."))