dr=read.table("FEV.txt",header=T,sep=",") plot(dr$Height,dr$FEV, ylab="FEV", xlab="Height") dr$Gender=factor(dr$Gender, levels=c(0,1), labels=c("Female", "Male")) dr$Smoke=as.factor(dr$Smoke) fit.lm=lm(dr$FEV~dr$Height) fit.lm fit.lm=lm(FEV~Height,data=dr) fit.lm fit.lm$coefficients confint(fit.lm) summary(fit.lm) library(car) ncvTest(fit.lm) crPlots(fit.lm) plot(fit.lm, which=4) durbinWatsonTest(fit.lm) box_lam=boxCox(fit.lm) lam=box_lam$x[which(box_lam$y==max(box_lam$y))] fit.lm.box=lm((dr$FEV^lam-1)/lam ~ dr$Height) plot(fit.lm.box) fit.lm=lm(FEV~Age,data=dr) summary(fit.lm) fit.lm=lm(FEV~Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age+Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age+Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age+Height*Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age+Age*Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height*Age+Smoke+Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Age*Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Height*Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Smoke*Age,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Gender*Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Age*Gender,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Smoke*Age+Height*Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Smoke*Age+Gender*Smoke,data=dr) summary(fit.lm) fit.lm=lm(FEV~Height+Age+Gender+Height*Age+Height*Gender+Smoke+Smoke*Age+Gender*Age,data=dr) summary(fit.lm) fitM.lm=lm(FEV~Height+Age+Gender+Smoke,data=dr) fitMI.lm=lm(FEV~Height+Age+Gender+Smoke+Height*Age+Height*Gender+Height*Smoke+Age*Gender+Age*Smoke+Gender*Smoke,data=dr) l_null=lm(FEV~1, data=dr) l_full=lm(FEV~Height*Age*Gender*Smoke, data=dr) res=step(l_null, scope=list(lower=l_null, upper=l_full), direction="forward")