Greetings, I'm using the screeplot command and in the R documentation it shows the general setup as screeplot(x, npcs = min(10, length(x$sdev)), type = c("barplot", "lines"), main = deparse(substitute(x)), ...) My question concerns labeling the screeplot and I see from the documentation that the main= function is referring to graphics parameters. I don't know what this means or where to find information on this. The plot automatically appears with the label "variances" on y-axis (which are actually the eigenvalues), and the label PCA on the top. I wish to relabel. Thanks in advance, David -- ======================================================================David Kaplan, Ph.D. Professor Department of Educational Psychology University of Wisconsin - Madison Educational Sciences, Room 1061 1025 W. Johnson Street Madison, WI 53706 email: dkaplan at education.wisc.edu Web: http://www.education.wisc.edu/edpsych/facstaff/kaplan/kaplan.htm Phone: 608-262-0836 Fax: 608-262-0843