Sorry, I hope this will be the last (for now, at least).
Following your advices, I did: n <- 100 anxiety <- c(rnorm(n, 10, 2.5), rnorm(n, 26, 3.2), rnorm(100, 25, 3.1), rnorm(100, 10, 2.6)) m.status <- c(rep('married', n*2), rep('not married', n*2)) gender <- c(rep('male', n), rep('female', n), rep('male', n), rep('female',n)) im <- as.integer(p2$m.status) m.status <- as.factor(m.status) gender <- as.factor(gender) require(rms) d <- datadist(gender, m.status); options(datadist='d') ols1 <- ols(anxiety ~ m.status) p1 <- Predict(ols1, m.status=.) ols2 <- ols(anxiety ~ m.status * gender) p2 <- Predict(ols2, m.status=., gender=.) pdf('figs/anova.pdf', height=6, width=8) par(mfrow=c(1,2), mar=c(4,4,1,1), cex=1.2) with(p1, plot(1:2, yhat, type='l', xlab='marital status', ylab='anxiety', ylim=c(5,30), lwd=1.2)) xyplot(yhat ~ im, groups=gender, type='l', data=p2, ylim=c(5,30), xlab='marital status', ylab='anxiety', scales=list(x=list(at=1:2, labels=levels(p2$m.status))), col=c('black','black'), lwd=1.2, label.curve=list(offset=unit(.3,"in"))) par(mfrow=c(1,1)) dev.off() Graphs are great! However, now, they does not appear in one panel. Sorry, again, for asking so many questions. I am trying to wrap this. Best, PM ______________________________________________ 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.