d <- read.table("exmp11-05.txt",header=TRUE,sep=",")
d$treat = as.factor(d$treat)
fit = aov(sleep~treat,data=d)
summary(fit)
qqnorm(fit$res);qqline(fit$res)
d2 = data.frame(x=abs(fit$res),treat=d$treat)
fit2 = aov(x~treat,data=d2)
summary(fit2)
fit3 = levene.test(d$sleep,d$treat,center=mean)
print(fit3)
TukeyHSD(fit)
plot(TukeyHSD(fit))
abline(v=0)