Peter, These things can be a little mysterious at the beginning. Lots of things in R are arranged in groups called packages (or libraries). Some basic ones come preinstalled with R, some you have to install yourself. If you type
library() at your R prompt you should get a list of all packages installed on your system. In order to use the functionality of a package you have to load it by specifying its name as an argument to the library call. For example, library(nlme) will load the package named "nlme" (if it is installed on your system) and give you the functionality of the nlme package, i.e. access to its functions.. Typing search() will show you what packages are already loaded on your system. Search.help will allow you to find in which package your function resides in. Typing search.help(polr) on my system returns polr(MASS) Proportional Odds Logistic Regression meaning that the polr function belongs to the package MASS which is installed on your system. The only thing remaining to do is typing library(MASS) Of course, if MASS is not installed on your system you will get nothing in response (actually you will get a message saying that nothing appropriate was found). Then, you would need to go to a CRAN site and use their search engine to find things about polr function. Hope this helps, Andy __________________________________ Andy Jaworski 518-1-01 Process Laboratory 3M Corporate Research Laboratory ----- E-mail: [EMAIL PROTECTED] Tel: (651) 733-6092 Fax: (651) 736-3122 |---------+---------------------------------------------------> | | "Peter Flom" <[EMAIL PROTECTED]> | | | Sent by: | | | [EMAIL PROTECTED]| | | ath.ethz.ch | | | | | | | | | 03/03/2004 14:42 | | | | |---------+---------------------------------------------------> >-----------------------------------------------------------------------------------------------------------------------------| | | | To: <[EMAIL PROTECTED]> | | cc: | | Subject: [R] Location of polr function | >-----------------------------------------------------------------------------------------------------------------------------| Hello I am running R 1.8.1 on a Windows platform I am attempting to fit an ordinal logistic regression model, using the polr function, as described in Venables and Ripley. But when I try model4 <- polr(ypsxcat~committed + as.factor(sex) + as.factor(drugusey) + anycsw + as.factor(sex)*committed + as.factor(sex)*as.factor(drugusey)+as.factor(sex)*anycsw, data = duhray) I get a message that the polr function was not found. Any help appreciated thanks Peter Peter L. Flom, PhD Assistant Director, Statistics and Data Analysis Core Center for Drug Use and HIV Research National Development and Research Institutes 71 W. 23rd St www.peterflom.com New York, NY 10010 (212) 845-4485 (voice) (917) 438-0894 (fax) ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html