# R script for lecture 8 in STK4900/9900

# Slide 18: Poisson regression -------------------------------------------------

car.claims <- read.table("http://www.uio.no/studier/emner/matnat/math/STK4900/data/car-claims.txt", header=TRUE)
fit.claims <- glm(acc~offset(log(num))+factor(age)+factor(vol), data=car.claims, family=poisson)
summary(fit.claims)


# Slide 21: Poisson regression - OR confidence intervals -----------------------

or.ci(fit.claims)



# Slide 23: Poisson regression  -----------------------

fit.null <- glm(acc~offset(log(num)), data=car.claims, family=poisson)
fit.age <- glm(acc~offset(log(num))+factor(age), data=car.claims, family=poisson)
fit.age.vol <- glm(acc~offset(log(num))+factor(age)+factor(vol), data=car.claims, family=poisson)
fit.interaction <- glm(acc~offset(log(num))+factor(age)+factor(vol) +factor(age):factor(vol), data=car.claims, family=poisson)

anova(fit.null,fit.age,fit.age.vol,fit.interaction,test="Chisq")