On 06-Dec-05 Berton Gunter wrote: > But note: There are (almost?) no situations in R where the dummy > variables coding is needed. The coding is (almost?) always handled > properly by the modeling functions themselves. > > Question: Can someone provide a "straightforward" example where the > dummy variable coding **is** explicitly needed?
Perhaps not particularly straightforward, but if you are using package 'mix' for multiple imputation where some variables are categorical and some continuous, the functions ecm.mix dabipf.mix both take a paremeter "design" which is a design matrix expressing dependency of the continuous variables on the categoricals. The R function 'model.matrix' is useful for obtaining this matrix. Best wishes, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <[EMAIL PROTECTED]> Fax-to-email: +44 (0)870 094 0861 Date: 06-Dec-05 Time: 22:39:44 ------------------------------ XFMail ------------------------------ ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
