adding an ellipse to a PCA plot
Dear John, Thanks, this actually works just fine! much easier than the ellipse-package! Lukas
On Monday, June 6, 2011, John Fox <jfox at mcmaster.ca> wrote:
Dear Lukas, You might try the dataEllipse() function in the car package. I hope this helps, ?John
-----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Lukas Baitsch Sent: June-06-11 10:33 AM To: r-help at r-project.org Subject: [R] adding an ellipse to a PCA plot Hi, I created a principal component plot using the first two principal components. I used the function princomp() to calculate the scores. now, I would like to superimpose an ellipse representing the center and the 95% confidence interval of a series of points in my plot (as to illustrate the grouping of my samples). I looked at the ellipse() function in the ellipse package but can't get it to work. the princomp()-function gives me the scores of each point, so I can calculate the mean and the 95%-CI, but I can't integrate this into the ellipse()-function). Is there a better way of doing this or can someone help me figure out this function? best regards, Lukas
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