fuel.r

rm(list=ls())

data = read.csv('weisberg_fuel.csv',header=TRUE)

X1 <- data$TAX # Tax
X2 <- data$DLIC
X3 <- data$INC
X4 <- data$ROAD

Y <- data$FUEL

df <- cbind(X1,X2,X3,X4,Y)
pairs(df)
summary(df)
cor(df)

fit <- lm(Y ~ X1+X2+X3+X4)
summary(fit)

# Anova
anova(fit)

# Use stepAIC
library(MASS)
stepAIC(fit)