# ANOREXIA-BEISPIEL FUER LINEARE MODELLE

library(MASS)
data(anorexia)
anorexia
ano <- split(anorexia,anorexia$Treat)
plot(ano$Cont$Prewt,ano$Cont$Postwt,
     xlim=c(min(anorexia$Prewt),max(anorexia$Prewt)),
     ylim=c(min(anorexia$Postwt),max(anorexia$Postwt)))
points(ano$CBT$Prewt,ano$CBT$Postwt,col='blue')
points(ano$FT$Prewt,ano$FT$Postwt,col='red')
abline(a=0,b=1,lty="dashed")
summary(lm(Postwt~Prewt,ano$Cont))
abline(a=92.0515,b=-0.1342)
summary(lm(Postwt~Prewt,ano$CBT))
abline(a=15.5772,b=0.8480,col='blue')
summary(lm(Postwt~Prewt,ano$FT))
abline(a=14.8198,b=0.9092,col='red')
summary(lm(Postwt~Prewt+Treat,anorexia))
summary(lm(Postwt~Prewt*Treat,anorexia))
summary(lm(Postwt~Prewt*Treat,anorexia))

modell <- lm(Postwt~Prewt*Treat,anorexia)
modell2 <- lm(Postwt~Prewt+Treat,anorexia)
anova(modell,modell2)
plot(anorexia$Prewt,residuals(modell))

plot(modell)