Dear all, I have a problem when I was working on Age-Period-Cohort study in R. I tried to put constraint to two coefficients on age (so that to solve the identification problem due to linear dependency). But I don't know how to do this in R(put constraint). If you could give me some suggestion, it will be very helpful! Oana
how to put constraint in R?
2 messages · Oana Mocila, Spencer Graves
1 day later
What are you trying to do? Suppose, for example, that you have a categorical variable representing 3 different age groups, and you want to estimate a linear model. As long as R recognizes the variable as categorical (of class "factor" or "ordered factor", R handles this automatically using "contrasts". If this is your question, I suggest you read about "factors", "Formulae for Statistical Models" and "Contrasts" in "An Introduction to R", which is the upper-left choice after 'help.start()' in recent versions of R (or downloadable from www.r-project.org -> Documentation -> Manuals). If you would like more help from this group, I believe you will increase your chances of getting quickly the information you seek in you PLEASE do read the posting guide! "www.R-project.org/posting-guide.html". hope this helps. spencer graves
Oana Mocila wrote:
Dear all, I have a problem when I was working on Age-Period-Cohort study in R. I tried to put constraint to two coefficients on age (so that to solve the identification problem due to linear dependency). But I don't know how to do this in R(put constraint). If you could give me some suggestion, it will be very helpful! Oana
______________________________________________ R-help at 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
Spencer Graves, PhD Senior Development Engineer PDF Solutions, Inc. 333 West San Carlos Street Suite 700 San Jose, CA 95110, USA spencer.graves at pdf.com www.pdf.com <http://www.pdf.com> Tel: 408-938-4420 Fax: 408-280-7915