- x
The generic argument. For the default method, this is a list of
covariance matrices. For the data.frame and matrix methods,
this is a numeric matrix of two or more columns supplying the variables to
be analyzed.
- ...
Other arguments passed to the default method for plot,
text, and points
- group
a factor defining groups, or a vector of length
n=nrow(x) doing the same. If missing, a single covariance ellipse is
drawn.
- pooled
Logical; if TRUE, the pooled covariance matrix for the
total sample is also computed and plotted
- method
the covariance method to be used: classical product-moment
("classical"), or minimum volume ellipsoid ("mve"), or minimum
covariance determinant ("mcd").
- data
For the formula method, a data.frame in which to evaluate.
- means
For the default method, a matrix of the means for all groups
(followed by the grand means, if pooled=TRUE). Rows are the groups,
and columns are the variables. It is assumed that the means have column
names corresponding to the variables in the covariance matrices.
- df
For the default method, a vector of the degrees of freedom for the
covariance matrices
- labels
Either a character vector of labels for the groups, or
TRUE, indicating that group labels are taken as the names of the
covariance matrices. Use labels="" to suppress group labels, e.g.,
when add=TRUE
- variables
indices or names of the response variables to be plotted;
defaults to 1:2. If more than two variables are supplied, the
function plots all pairwise covariance ellipses in a scatterplot matrix
format.
- level
equivalent coverage of a data ellipse for normally-distributed
errors, defaults to 0.68.
- segments
number of line segments composing each ellipse; defaults to
40.
- center
If TRUE, the covariance ellipses are centered at the
centroid.
- center.pch
character to use in plotting the centroid of the data;
defaults to "+".
- center.cex
size of character to use in plotting the centroid (means) of the
data; defaults to 2.
- col
a color or vector of colors to use in plotting ellipses---
recycled as necessary--- see Details. A single color can be given, in which case it is used
for all ellipses. For convenience, the default colors for all plots
produced in a given session can be changed by assigning a color vector via
options(heplot.colors =c(...). Otherwise, the default colors are
c("red", "blue", "black", "darkgreen", "darkcyan", "magenta", "brown", "darkgray").
- lty
vector of line types to use for plotting the ellipses---
recycled as necessary--- see Details. Defaults to 1.
- lwd
vector of line widths to use for plotting the ellipses---
recycled as necessary--- see Details. Defaults to
2.
- fill
A logical vector indicating whether each ellipse should be
filled or not--- recycled as necessary--- see Details. Defaults to FALSE.
- fill.alpha
Alpha transparency for filled ellipses, a numeric scalar
or vector of values within [0,1], where 0 means fully transparent and
1 means fully opaque. Defaults to 0.3.
- label.pos
Label position, a vector of integers (in 0:4) or
character strings (in c("center", "bottom", "left", "top", "right"))
use in labeling ellipses, recycled as necessary. Values of 1, 2, 3 and 4,
respectively indicate positions below, to the left of, above and to the
right of the max/min coordinates of the ellipse; the value 0 specifies the
centroid of the ellipse object. The default, label.pos=NULL
uses the correlation of the ellipse to determine "top" (r>=0) or
"bottom" (r<0).
- xlab
x-axis label; defaults to name of the x variable.
- ylab
y-axis label; defaults to name of the y variable.
- vlabels
Labels for the variables can also be supplied through this
argument, which is more convenient when length(variables) > 2.
- var.cex
character size for variable labels in the pairs plot, when length(variables) > 2.
- main
main plot label; defaults to "", and presently has no
effect.
- xlim
x-axis limits; if absent, will be computed from the data.
- ylim
y-axis limits; if absent, will be computed from the data.
- axes
Whether to draw the x, y axes; defaults to TRUE
- offset.axes
proportion to extend the axes in each direction if
computed from the data; optional.
- add
if TRUE, add to the current plot; the default is
FALSE. This argument is has no effect when more than two variables
are plotted.