@JLucke: As for the africa variable: I took it out of the model, so that we can exclude this variable itself and collinearity between the africa and the litrate variable as causes for the litrate-problem. This also removed the singularity remark at the top. However, the problem with litrate-variable seen as many factors remains.
Just to clarify: The second results table is fictional to explain where I was headed with my regression. Anyway, thanks for the quick answer. @David: Thanks for the pointer. It was in fact a bad variable, but I created it myself. I changed the set halfway in between my calculations and thought I had adjusted everything. It turns out, that I forgot to adjust the set-length which is re-set in between the two steps of my Heckman-procedure. In any case: Thanks for the quick and helpful reply. :-) -- View this message in context: http://r.789695.n4.nabble.com/Regression-Error-Otherwise-good-variable-causes-singularity-Why-tp2322780p2322925.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
