Dieter Menne: Thank you for your reply! I know that I don't have to do any logit , but I want to understand how R fit the glm models. I will read the examples your suggested . Best regards, Bin Yue
Dieter Menne wrote: > > Bin Yue <leffgh <at> 163.com> writes: > >> After reading the following two links: >> http://luna.cas.usf.edu/~mbrannic/files/regression/Logistic.html >> http://www.tufts.edu/~gdallal/logistic.htm >> I've known the mathematical basis for logistic regression.However I >> am >> still not so sure about the "logit " >> For a categorical independent variable, It is easy to understand >> the >> procedures how "log odds" are calculated. As I know, First the >> observations >> are grouped according to the IV and DV, generating a contingency table. > .. >> My problem is this : in my data set , the IVs are continuous >> variables, >> do I still have to generate such a table and compute the log odds for >> each >> level of IV according to which the log odds are calculated? > > Let's assume you are going to use glm in package stats. glm can be fed > with > data in three ways; in your case, you should use the "one-row/one 0-1 > event" > format, that is the "long" style. You do not have to compute any logit, > glm will do that for your. > > The example coming closest to your's is the birthwt example in > MASS/scripts/ch07.R and chapter 7 in Venables/Ripley MASS. Try to > generate > a small, self-running example with a data set similar to your's, and you > have > a good chance to get a more detailed answer. > > Dieter > > ______________________________________________ > 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. > > ----- Best regards, Bin Yue ************* student for a Master program in South Botanical Garden , CAS -- View this message in context: http://www.nabble.com/the-observed-%22log-odds%22-in-logistic-regression-tp14267125p14269459.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.
