crabdata=read.csv(file='table-4-3.csv')
attach(crabdata)
library(MASS)
summary(glm(satell ~ width, family=poisson))
summary(glm.nb(satell ~ width))
summary(glm(satell ~ weight, family=poisson))
summary(glm.nb(satell ~ weight))

breaks=c(0,23.25,24.25,25.25,26.26,27.25,28.25,29.25,Inf)
bins=cut(width,breaks=breaks,dig.lab=4)
cases=table(bins)
wdbinned=tapply(width,bins,mean)
satbinned=tapply(satell,bins,mean)
crabbinned=data.frame(cbind(width=wdbinned,cases=cases,satell=satbinned))
summary(glm(satell ~ width, family=poisson(link=identity),data=crabbinned))
summary(glm.nb(satell ~ width,data=crabbinned))
summary(glm.nb(satell ~ width,data=crabbinned[2:8,]))


