# ConcEllipse: Concentration ellipse for a se of two-dimensional points In MultBiplotR: Multivariate Analysis Using Biplots in R

 ConcEllipse R Documentation

## 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.