Hi Galandis, dudi.mix() in package ade4 does PCA using categorical and/or quantitative variables. Ordered cats are replaced by poly(x, deg=2). Squares of categoricals can also be used. The method is a generalization by Chessel of the method of Hill and Smith.
Regards, Mark. Galanidis Alexandros wrote: > > Hi all, > > I' m trying to figure out if it is appropriate to do a PCA having only > categorical data (not ordinal). I have only find the following quote: > > One method to find such relationships is to select appropriate variables > and > to view the data using a method like Principle Components Analysis (PCA) > [4]. > This approach gives us a clear picture of the data using KL-plot of the > PCA. > However, the method is not settled for the data including categorical > data. > [http://hp.vector.co.jp/authors/VA038807/personal/covEigGiniRep17.pdf] > > but I'm still not sure if it WRONG to do so. > > Any opinion or reference would be very helpful > > thanks > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/PCA-and-categorical-data-tp22368671p22369249.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.
