Hello Lady or Sir, I want to do model selection with 'step' function. But there is a trouble to me.
For example, there are 5 independent variables, X0,X1,X2,X3 and X4; and 1 dependent variable y. I want to run stepwise regression y ~ X0 + X1 + X2 + X3 + X4, and I want to keep X0 always in the model. Every time when I run command 'step' with 'keep', error information "could not find function 'keep' " is always shown. Could you tell me how to use the parameter 'keep' in 'step' function? Thank you very much and best regards, Wenxin Liu 2009.11.02 ------------------------------------------------------------------------------------- Wenxin Liu, Postdoc., Scientific staff State Plant Breeding Institute(720) University of Hohenheim 70593 Stuttgart, Germany PhoneNo.: +49-(0)711-459-22670 Telefax : +49-(0)711-459-23841 Email : wenxin....@uni-hohenheim.de (academic) or lwx.bios...@gmail.com (personal) [[alternative HTML version deleted]] ______________________________________________ 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.