pdf("gettysburg.pdf")

g0 <- read.fwf("C:\\data\\gettysburg1.dat", width=c(8,8,8,8,8,8,8),
 col.names=c("division", "officer", "totsoldier", "killed", "wounded", "captmiss", "noncaslty"))

casualty = g0$killed + g0$wounded + g0$captmiss

probcaslty = casualty/g0$totsoldier

g1 <- data.frame(division=factor(g0$division), officer=g0$officer, probcaslty=probcaslty, totsoldier=g0$totsoldier)

attach(g1)

g1

cas.mod1 <- glm(probcaslty ~ 1 , binomial("logit"), weights=totsoldier, data=g1)

summary(cas.mod1)

cas.mod2 <- glm(probcaslty ~ 1 + officer, binomial("logit"), weights=totsoldier)

summary(cas.mod2)

cas.mod3 <- glm(probcaslty ~ 1+ officer + division, binomial("logit"), weights=totsoldier)

summary(cas.mod3)

cas.mod4 <- glm(probcaslty ~ 1+officer + division + officer:division, binomial("logit"), weights=totsoldier)

summary(cas.mod4)

dev.off()