Dear all, I have a question on glm, family binomial. I do not see significant differences between the levels of a factor (treatment) if all data for a level is 0; and replacing a 0 for a 1 (in fact reducing the difference), then I detect the significant difference that I expected. Is there a way to overcome this problem? or this is an expected behaviour ? Here is an example:
s <- c(2,4,4,5,0,0,0,0) f <- c(31,28,28,28,32,37,34,35) tr <- gl(2, 4) sf <- cbind(s,f) # numbers of successes and failures summary(glm(sf ~ tr, family="binomial")) # tr ns sf[8,1] <- 1 summary(glm(sf ~ tr, family="binomial")) # tr significative ** Thanks for any suggestion Juli -- http://www.ceam.es/pausas ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
