pdf("webwool1.pdf")

ww1 <- read.fwf("C:\\data\\webworm1.dat", width=c(8,8,8,8,8),
col.names=c("trt", "wwcount", "t2dum", "t3dum", "t4dum"))

ww2 <- data.frame(trt=factor(ww1$trt), wwcount=ww1$wwcount,
t2dum=ww1$t2dum, t3dum=ww1$t3dum, t4dum=ww1$t4dum)

attach(ww2)


ww21 <- subset(ww2,trt==1)
ww22 <- subset(ww2,trt==2)
ww23 <- subset(ww2,trt==3)
ww24 <- subset(ww2,trt==4)

#ww21
#ww22
#ww23
#ww24

poi1 <- glm(formula = wwcount ~ 1, family=poisson(link=log), data=ww21)
summary(poi1)

poi2 <- glm(formula = wwcount ~ 1, family=poisson(link=log), data=ww22)
summary(poi2)

poi3 <- glm(formula = wwcount ~ 1, family=poisson(link=log), data=ww23)
summary(poi3)

poi4 <- glm(formula = wwcount ~ 1, family=poisson(link=log), data=ww24)
summary(poi4)

library(MASS)

nb1 <- glm.nb(formula = wwcount ~ 1, data=ww21)
summary(nb1)

nb2 <- glm.nb(formula = wwcount ~ 1,data=ww22)
summary(nb2)

nb3 <- glm.nb(formula = wwcount ~ 1, data=ww23)
summary(nb3)

nb4 <- glm.nb(formula = wwcount ~ 1, data=ww24)
summary(nb4)

dev.off