MultBiplotR (version 23.11.0)

ConcEllipse: 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)

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

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.

Author

Jose Luis Vicente Villardon

Details

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

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)