I think the covariance between dummy variables or between dummy variables and intercept should always be zero. meaning: no sigularity problem??
rlearner309 wrote: > > This is actually more like a Statistics problem: > I have a dataset with two dummy variables controlling three levels. The > problem is, one level does not have many observations compared with other > two levels (a couple of data points compared with 1000+ points on other > levels). When I run the regression, the result is bad. I have unbalanced > SE and VIF. Does this kind of problem also belong to "near sigularity" > problem? Does it make any difference if I code the level that lacks data > (0,0) in stead of (0,1)? > > thanks a lot! > -- View this message in context: http://www.nabble.com/A-regression-problem-using-dummy-variables-tp18214377p18237666.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.
