y=dget("rats.dat")
x = c(8.0, 15.0, 22.0, 29.0, 36.0)
xbar = 22; #mean y
N = 30; #number of rats
T = 5; #number of repeated measures
group=c(rep(1,15),rep(2,15))

pdf("rats.data.pdf", width=4, height=4, horiz=FALSE)
plot(0,0,type="n",xlab="day",ylab="weight of rats", main="",xlim=range(x), ylim=range(y))
for (i in 1:N) {
   lines(x,y[i,],col=group[i])
}
legend(25, 180, c("trt 1", "trt 2"), col=1:2, bty="n", lty=1)
dev.off()