I figured this out so I wanted to post a response to my own question. Thanks to Brian Ripley for his hint, which got me looking in the right direction. The plot I had seen before that I wanted was automatic output to the cor.plot command in the mvoutlier library. A similar tolerance ellipse can be obtained from the covPlot command in the robustbase library, using which="tolEllipsePlot" and classic=T.
Dr. Jenifer Larson-Hall Assistant Professor of Linguistics University of North Texas (940)369-8950 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
