ConcEllipse: Concentration ellipse for a se of two-dimensional points

In MultBiplotR: Multivariate Analysis Using Biplots in R

Concentration ellipse for a se of two-dimensional points

Description

The function calculates a non-parametric concentration ellipse for a set of two-dimensional points.

Usage

ConcEllipse(data, confidence=1, npoints=100)

Arguments

data	The set of two-dimensional points
confidence	Percentage of points to be included in the ellipse
npoints	Number of points to draw the eelipse contour. The hier the number of points the smouther is the ellipse.

Details

The procedre uses the Mahalanobis distances to determine the points that will be used for the calculations.

Value

A list with the following fields

data	Data Used for the calculations
confidence	The confidence level used
ellipse	The points on the ellipse contour to be plotted
center	The center of the points

Author(s)

Jose Luis Vicente Villardon

References

Meulman, J. J., & Heiser, W. J. (1983). The display of bootstrap solutions in multidimensional scaling. Murray Hill, NJ: Bell Laboratories.

Linting, M., Meulman, J. J., Groenen, P. J., & Van der Kooij, A. J. (2007). Stability of nonlinear principal components analysis: An empirical study using the balanced bootstrap. Psychological Methods, 12(3), 359.

Examples

data(iris)
dat=as.matrix(iris[1:50,1:2])
plot(iris[,1], iris[,2],col=iris[,5], asp=1)
E=ConcEllipse(dat, 0.95)
plot(E)

MultBiplotR documentation built on Nov. 21, 2023, 5:08 p.m.