In https://stat.ethz.ch/pipermail/r-help/2008-March/156868.html I found what linear separability means. But what can I do if I find such a situation in my data? Field (2005) suggest to reduce the number of predictors or increase the number of cases. But I am not sure whether I can, as an alternative, take the findings from my analysis and report them. And if so, how can I find the linear combination of the predictors that separates the zeros from the ones?
Below a small example to illustrate the situation. set.seed(123) df <- data.frame( 'y'=c(rep(FALSE, 6), rep(TRUE, 14)), 'x1'=c(sample(1:2, 6, repl=T), sample(3:5, 14, repl=T)), 'x2'=c(sample(4:7, 6, repl=T), sample(1:3, 14, repl=T)), 'x3'=round(rnorm(20, 4, 2), 0) ) df[17:18, c(2, 3)] <- df[17:18, c(3, 2)] glm(y ~ ., data=df[, -3], family=binomial("logit")) glm(y ~ ., data=df, family=binomial("logit")) Thanks, Sören -- Sören Vogel, Dipl.-Psych. (Univ.), PhD-Student, Eawag, Dept. SIAM http://www.eawag.ch, http://sozmod.eawag.ch ______________________________________________ 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.