Long <- read.table( "http://socserv.socsci.mcmaster.ca/jfox/Books/Applied-Regression-2E/datasets/Long.txt", header=TRUE) attach(Long) tab <- table(art) x <- sort(unique(art)) windows(width=5, height=5) plot(x, tab, type='h', xlab='Number of Articles', ylab='Frequency') points(x, tab, pch=16) abline(h=0, lty=2) detach(Long) mod.long <- glm(art ~ ., data=Long, family=poisson) summary(mod.long) exp(coef(mod.long)) mod.long.od <- update(mod.long, family=quasipoisson) summary(mod.long.od)