[R] Question on binomial data

[ehud cohen]

Hi,

We have an experiment with pass/fail outcome, and a continuous
parameter which may contribute to the outcome.

First, we've analyzed it by:

p=c(F,T,F,F,F,T,T,T,T,T,T,T,F,T,T,T,T);
w=c(53,67,59,59,53,89,72,56,65,63,62,58,59,72,61,68,63);
l<-glm(p~w,family=binomial)
summary(l)

Which turned out to be non significant.

Then, we thought of comparing the parameters of the two groups (passed
vs. failed)

t.test(w[which(p)],w[which(!p)],alternative="two.sided")

which turned highly significant.

I'd appreciate some insight...

Thanks, Ehud.