Dear R Users, I'm very very interested in learning how to use R to carry out a classification of data using discriminant function analysis. I've found the MASS package and the lda function, but the examples in the help system are a bit over my head. I'm not exactly sure how to interpret the output, for example, of if the inputs I've chosen are best suited to my needs. I was hoping I could converse with a lister or two to help me get started on the road to involving R in this project. (I'm willing to carry on the conversation using the R-users list, but I am wary of abusing the list.) The alternative to R is for me to use SPSS. It's what we've used up until now, but nobody loves it. The undergraduates that I'm working with would have a much better learning experience if they were able to explore our multivariate with data using R. By students and I have data sets with sixteen continuous variables, and DFA has been shown to do a reasonable job of classifying the origin of a new datum correctly. We want to learn how to do this ourselves so that we can work on improving the DFA model by adding new variables or modifying the nature of the data sets we work with in a "natural way." If you are willing to answer questions and can help me get to the point where I can use R to do some of my analysis, I'd write up what I learned about using the tool and make it available on my website and on http://mathbio.truman.edu. So, if you can help, please shoot me a note. Thanks in advance. Jason ===============================================================Jason E. Miller, Ph.D. Associate Professor of Mathematics Truman State University Kirksville, MO http://pyrite.truman.edu/~millerj/ 660.785.7430
In message <200503301005.j2UA3CBr019053 at hypatia.math.ethz.ch>, r-help- request at stat.math.ethz.ch writes>Dear R Users, > >I'm very very interested in learning how to use R to carry out a >classification of data using discriminant function analysis. I've >found the MASS package and the lda function, but the examples in the >help system are a bit over my head. I'm not exactly sure how to >interpret the output, for example, of if the inputs I've chosen are >best suited to my needs.[...] I would recommend writing your own simple version of lda in R. For example, stick to two class problems, and don't worry too much about efficiency or dealing with bad input. Then think about how you might make your routines of more general use (but don't bother to implement this). This is a good way of learning R, and having got this far on your own, you will find the documentation and examples for lda make sense. Well, it worked for me. Here's some useful functions: ?"%*%" ?t ?determinant ?solve ?mean ?cov ?cat ?scan -- Graham Jones, author of SharpEye Music Reader http://www.visiv.co.uk 21e Balnakeil, Durness, Lairg, Sutherland, IV27 4PT, Scotland, UK