Tools<-read.csv('Tools.csv')
Tools$oil<-as.factor(Tools$oil)
str(Tools)

plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
dev.print(pdf,file='Tools0.pdf',width=11,height=9)


plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
text(Tools$rpm,Tools$y+2,Tools$tool)
dev.print(pdf,file='Tools1.pdf',width=11,height=9)

plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
text(Tools$rpm,Tools$y+2,Tools$oil)
dev.print(pdf,file='Tools2.pdf',width=11,height=9)

fit1<-lm(y~rpm,data=Tools)
summary(fit1)

plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
abline(fit1)
dev.print(pdf,file='Tools3.pdf',width=11,height=9)

fit2<-lm(y~rpm+tool,data=Tools)
summary(fit2)
plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
abline(fit2$coef[1],fit2$coef[2])
abline(fit2$coef[1]+fit2$coef[3],fit2$coef[2],lty=2)
legend(800,50,c("A","B"),lty=c(1,2))
title("rpm+tool")
dev.print(pdf,file='Tools4.pdf',width=11,height=9)

drop1(fit2,test='F')
anova(lm(y~rpm+tool,data=Tools))
anova(lm(y~tool+rpm,data=Tools))
anova(fit1,fit2)


fit3<-lm(y~rpm+tool+rpm:tool,data=Tools)
summary(fit3)
plot(Tools$rpm,Tools$y,pch=19,ylim=range(0,50),xlab='rpm',ylab='Lifetime (hrs)')
abline(fit3$coef[1],fit3$coef[2])
abline(fit3$coef[1]+fit3$coef[3],fit3$coef[2]+fit3$coef[4],lty=2)
legend(800,50,c("A","B"),lty=c(1,2))
title("rpm+tool+rpm:tool")
dev.print(pdf,file='Tools5.pdf',width=11,height=9)

drop1(fit3,test='F')
anova(fit3)
anova(fit2,fit3)

###############################################################

fit5<-lm(y~tool+oil,data=Tools)
summary(fit5)
anova(fit5)
drop1(lm(y~tool+oil,data=Tools),test='F')

fit6<-lm(y~oil+tool,data=Tools)
summary(fit6)
anova(fit6)

anova(lm(y~tool+oil,data=Tools))
anova(lm(y~oil+tool,data=Tools))

table(Tools$tool,Tools$oil)

###############################################################
fit4<-lm(y~rpm+tool+oil,data=Tools)
summary(fit4)

drop1(fit4,test='F')

anova(fit2,fit4)