Dear All, I need to produce a multi-panel plot where: 1) groups within panels receive distinct symbols; 2) a linear regression is fit to the entire panel, not the individual groups; 3) a common abline is plotted in each panel. Essentially I would like to merge the two plots below, but I can't seem to figure out how to call both lmline and abline, and also retain the grouping symbols. In addition, I have not yet figured out how to place the 'Key()' in the empty grid cell. Please see the example code below. Note that I am running R2.2.1 on windows. Any help would be greatly appreciated. Thanks for your time, Dan library(Hmisc) windows(record=TRUE) panelgrp=rep(LETTERS[1:3], 20) sites=c(rep("d", 15), rep("e", 15), rep("f", 15), rep("g", 15)) data1=data.frame(panelgrp=factor(panelgrp), sites=factor(sites)) data1$pred=runif(60) data1$resp=runif(60) lmcoef=lm(resp~pred, data=data1[data1$panelgrp=="A",]) xYplot(resp~pred|panelgrp, groups=sites, data=data1, pch=c(1,2,3,4), abline=list(a=lmcoef$coefficients[1], b=lmcoef$coefficients[2], lty=2)) Key() xYplot(resp ~ pred|panelgrp, groups=sites, pch=c(1,2,3,4), data=data1, panel = function(x, y) { panel.xyplot(x,y) panel.lmline(x,y, span=1) } ) -- Daniel E. Bunker BioMERGE Associate Director Post-Doctoral Research Scientist Columbia University Department of Ecology, Evolution and Environmental Biology 1200 Amsterdam Avenue New York, NY 10027-5557 deb37ATcolumbiaDOTedu 212-851-1888 phone 212-854-8188 fax