# Oneway ANOVA for CRD

data <- read.table("c:/courses/st526/r/oneway.txt",header=T)

order    <- data[,1]
machine  <- as.character(data[,2])
strength <- data[,3]
operator <- data[,4]

aovdata <- data.frame(order,machine,strength)

#----------This gives the ANOVA results using "aov" ----------------

f1 <- aov(strength~machine,data=aovdata) 
summary (f1)

windows()
par(mfrow=c(2,3))
plot(fitted(f1),resid(f1),main="Residuals vs Predicted Values")
abline(h=0)
qqnorm(resid(f1),main="Normal Probability Plot")
hist(resid(f1),nclass=10,main="Histogram of Residuals")
stripchart(resid(f1)~machine,vertical=TRUE,main="Residuals vs Machine")
abline(h=0)
stripchart(resid(f1)~operator,vertical=TRUE,main="Residuals vs Operator")
abline(h=0)
plot(order,resid(f1),main="Residuals vs Run Order")
abline(h=0)

#----------This gives the ANOVA results using "lm" ----------------

f2 <- lm(strength~machine,data=aovdata)
summary(f2)

windows()
par(mfrow=c(2,3))
plot(fitted(f2),resid(f2),main="Residuals vs Predicted Values")
abline(h=0)
qqnorm(resid(f2),main="Normal Probability Plot")
hist(resid(f2),nclass=10,main="Histogram of Residuals")
stripchart(resid(f2)~machine,vertical=TRUE,main="Residuals vs Machine")
abline(h=0)
stripchart(resid(f2)~operator,vertical=TRUE,main="Residuals vs Operator")
abline(h=0)
plot(order,resid(f2),main="Residuals vs Run Order")
abline(h=0)