pdf("ex_02_01a.pdf") package <- c(rep(1:4,each=3)) logcount <- c(7.66,6.98,7.80,5.26,5.44,5.80,7.41,7.33,7.04,3.51,2.91,3.66) bacteria <- data.frame(package,logcount) attach(bacteria) bacteria package <- factor(package) tapply(logcount,package,mean) tapply(logcount,package,sd) ex_02_01.mod <- aov(logcount ~ package) summary.lm(ex_02_01.mod) anova(ex_02_01.mod) ex_02_01a.mod <- aov(logcount ~ package -1) summary.lm(ex_02_01a.mod) anova(ex_02_01a.mod) dev.off()