cereals1 <- read.table("c:/cjw/sasdata/st550/cereals.txt",header=TRUE)

cereals1$midshelf <- (cereals1$shelf == 2) 

cereals2 <- cereals1[cereals1$sugars >= 0,]
cereals2 <- cereals2[cereals2$manufacturer != 'A',]

cereals2.glm1 <- glm(midshelf ~ sugars,data=cereals2,family=binomial())

summary(cereals2.glm1)

par(mfrow=c(2,2)) 
plot(cereals2.glm1)
par(mfrow=c(1,1))