ellipse.mvdalab: Ellipses, Data Ellipses, and Confidence Ellipses

In mvdalab: Multivariate Data Analysis Laboratory

Ellipses, Data Ellipses, and Confidence Ellipses

Description

This function draws econfidence ellipses for covariance and correlation matrices derived from from either a matrix or dataframe.

Usage

ellipse.mvdalab(data, center = c(0, 0), radius = "chi", scale = TRUE,
  segments = 51, level = c(0.95, 0.99), plot.points = FALSE, pch = 1, size = 1,
  alpha = 0.5, verbose = FALSE, ...)

Arguments

data	A dataframe
center	2-element vector with coordinates of center of ellipse.
radius	Use of the Chi or F Distributions for setting the radius of the confidence ellipse
scale	use correlation or covariance matrix
segments	number of line-segments used to draw ellipse.
level	draw elliptical contours at these (normal) probability or confidence levels.
pch	symbols to use for scores
size	size to use for scores
alpha	transparency of scores
plot.points	Should the points be added to the graph.
verbose	output results as a data frame
...	additional arguments. Currently ignored.

Details

ellipse uses the singular value decomposition in order to generate the desired confidence regions. The default confidence ellipse is based on the chisquare statistic.

Value

Returns a graph with the ellipses at the stated as levels, as well as the ellipse coordinates.

Author(s)

Nelson Lee Afanador ([e-mail])

References

Fox, J. (2008) Applied Regression Analysis and Generalized Linear Models, Second Edition. Sage.

Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage.

Examples

data(iris)
ellipse.mvdalab(iris[, 1:2], plot.points = FALSE)
ellipse.mvdalab(iris[, 1:2], center = colMeans(iris[, 1:2]), plot.points = TRUE)

mvdalab documentation built on Oct. 6, 2022, 1:05 a.m.