# RCBD  Ex. 4.1 p. 144~ 150 
x <-scan("vascgraft.txt")
PSI.labels <- c(8500,8700,8900,9100)
vasc.graft <- data.frame(PSI=gl(4,6,24),block=gl(6,1,24),x)
vasc.graft.aov <- aov(x~block+PSI,vasc.graft)
# Table 4.4 p. 145
summary(vasc.graft.aov)  



# If treated as CRD, Table 4.5 p. 146
vasc.graft.CRDaov <- aov(x~PSI,vasc.graft)
summary(vasc.graft.CRDaov)

# Multiple tests for PSI pairwise comparison with familywise sig level .05
TukeyHSD(vasc.graft.aov, "PSI")
# c.f. 
TukeyHSD(vasc.graft.CRDaov, "PSI")

# Standard plots for model checking

opar <- par(mfrow=c(2,2),cex=.8)
plot(vasc.graft.aov)
par(opar)