## Load the data
airlinesData <- read.table("Table16_1.csv", header = TRUE)


###----------------------------------------------------------------------------
### The fixed effect model
###----------------------------------------------------------------------------

## You can create dummies and estimate the model with OLS

## Or we do it in with lm()
airlinesFixed <- lm(C~ factor(I) + Q + PF + LF, data = airlinesData)
summary(airlinesFixed)
AIC(airlinesFixed)

airlinesFixed2 <- lm(C~  Q + PF + LF, data = airlinesData)
AIC(airlinesFixed2)
###----------------------------------------------------------------------------
### The random effect model
###----------------------------------------------------------------------------

## Install the package (you need Internet connection)
## install.packages("nlme")

## Load the package
require(nlme)

## The random effect model
airlinesRandom <- lme(C~ Q + PF + LF, random = ~ 1|I,  data = airlinesData)
summary(airlinesRandom)