data(trees)
names(trees)
attach(trees)
par(mfrow=c(1,2))
plot(log(Girth),log(Volume))
plot(log(Height),log(Volume))
Radius<-Girth/12/2/pi
model1<-lm(log(Volume)~log(Radius)+log(Height))
summary(model1)
model1<-glm(log(Volume)~log(Radius)+log(Height))
model2<-glm(log(Volume)~offset(2*log(Radius)+log(Height)))
model3<-glm(log(Volume)~-1+offset(1.14473+2*log(Radius)+log(Height)))
anova(model1,model2,model3,test="F")
