x<-matrix(scan(file='pema.dat'),ncol=2,byrow=T)
lserum<-log(x[,2])
drug<-factor(rep(LETTERS[1:4],c(7,7,7,7)))
pema.df<-data.frame(drug,lserum)
aov1<-aov(lserum~drug,pema.df)
plot(fitted.values(aov1),residuals(aov1),xlab='Fitted Values',
ylab='Residuals')
