The function calculates a non-parametric concentration ellipse for a set of two-dimensional points.
ConcEllipse(data, confidence=1, npoints=100)A list with the following fields
Data Used for the calculations
The confidence level used
The points on the ellipse contour to be plotted
The center of the points
The set of two-dimensional points
Percentage of points to be included in the ellipse
Number of points to draw the eelipse contour. The hier the number of points the smouther is the ellipse.
Jose Luis Vicente Villardon
The procedre uses the Mahalanobis distances to determine the points that will be used for the calculations.
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.
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)
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