pdf("amoeba.pdf")

amoeba1 <- read.fwf("C:\\data\\entozamoeba.dat", width=c(8,8), col.names=c("Trt", "Yield"))

fTrt <- factor(amoeba1$Trt, levels=1:5)

levels(fTrt) <- c("None", "H", "F", "HF", "FH")

amoeba <- data.frame(amoeba1, fTrt)

amoeba

attach(amoeba)

tapply(Yield, fTrt, mean)

tapply(Yield, fTrt, sd)

amoeba1.aov <- anova(lm(Yield~fTrt))

amoeba1.aov

amoeba.res <- residuals(amoeba1.aov)

hist(amoeba.res)

# Obtain Tukey's Comparisons among levels of treatment

TukeyHSD(amoeba1.aov, "fTrt")


pairwise.t.test(Yield, fTrt, p.adj="bonf")

bartlett.test(Yield~fTrt)

dev.off()