As the subject implies, I am trying to draw a joint confidence interval of two variables, using the "ellipse" package. However, the ellipse() function plots an ellipsoid that is far too large than what I get when I calculate the limits by hand. For the t option, I am using sqrt(qf(level, df1, df2)) as I believe that I should be. I am giving a variance-covariance matrix as the object argument. Anyone have a simple idea of what may be going on? I would have to scale t by about 1/4 to get it in the right neighbourhood. Thanks in advance, Chris Fonnesbeck -- ~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* Christopher J. Fonnesbeck Ph.D. Student Georgia Co-operative Wildlife Unit University of Georgia Athens, GA 30602 Email: cjf at fonnesbeck.net Yahoo: fonnesbeck_chris ~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._