Output from the multinom-function
Dear Mike, I have some lecture notes on logistic regression, available at <http://socserv.socsci.mcmaster.ca/jfox/Courses/soc740/chap15-overheads.pdf>, which briefly describe the multinomial logit model; look in the section on modeling polytomous data. You'd probably do well to read a text that covers the subject; J. Long, Regression Models for Categorical and Limited Dependent Variables (Sage, 1997) is quite accessible. John
At 02:58 AM 12/12/2001 -0800, Hoodoo Gooroo wrote:
Hello folks, Let me first apologize: I'm not a professional nor a mathematician, just an ordinary guy, fooling around with the excellent R-package. I know the basic principles behind statistics, but haven't read anything more advanced than the ordinary first probability and statistics courses. Enough disclaimers? Good! I was examining the multinom-function (in the nnet-package) the other day and run a couple of tests. This is part of an output I got. multinom(formula = result ~., data = info) Coefficients: (Intercept) PH WH 1 -0.3974387 0.02201908 -0.0009618038 2 2.5183566 -0.07076967 -0.0596189836 The variable result I was trying to predict is a nominal variable, taking the values 0, 1 and 2. The independent variables are quite a few, some of them nominal, some not. I know about regression coefficients, intercepts, and all that jazz. I'm not sure, though, how I should use the coefficients and intercepts I got in the output. Why are there two different coefficients per variable? When should I use which? How should I interpret the output of the regression function? Should the output be rounded to the nearest integer, which would happen to be <=0, 1 or >=2 -> I can decide which the prediction is? Or am I missing some fine points in this particular field of math I'm (admittedly somewhat blindfolded) messing around in? I'm grateful for any help, or any pointers to good sources on the web. I don't have any problems with reading theory - it's just that I don't have any theory to read! Thanks a lot in advance, Mike
----------------------------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario, Canada L8S 4M4 email: jfox at mcmaster.ca phone: 905-525-9140x23604 web: www.socsci.mcmaster.ca/jfox ----------------------------------------------------- -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._