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Stella, An obvious answer is ?step However, I'm having a bit of a problem with it, lately. I got it wording with backwards selection, then it didn't work when I changed the "direction" from "backward" to "both" (backwards and forwards). I would like to know whatever you find that works. Also, look at the procedures for logistic regression in the Design package. regards, Farrar Sergio Della Franca <sergio.della.franca@gmail.com> wrote: Dear R-Helpers, I'd like to perform a Logistic Regression whit a Stepwise method. Can you tell me how can i proceed to develop this procedure? Thank you in advance. Sergio Della Franca. [[alternative HTML version deleted]] ______________________________________________ R-help@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 and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]]
Sergio Della Franca wrote:> Dear R-Helpers, > > I'd like to perform a Logistic Regression whit a Stepwise method. > > > Can you tell me how can i proceed to develop this procedure? > > > Thank you in advance. > > > Sergio Della Franca.If the number of events is not incredibly large, you can get almost the same result with the following code :-) candidates <- setdiff(names(mydataframe), 'y') p <- length(candidates) sample(candidates, sample(round(p/4):round(p/2), 1)) -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University
Rich Ulrich has compiled some posts (I believe from the S list) on some of
the dangers of stepwise regression:
http://www.pitt.edu/~wpilib/statfaq/regrfaq.html
Regards,
-Cody
"Sergio Della
Franca"
<sergio.della.fra To
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[R] Stepwise Logistic Regression
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Dear R-Helpers,
I'd like to perform a Logistic Regression whit a Stepwise method.
Can you tell me how can i proceed to develop this procedure?
Thank you in advance.
Sergio Della Franca.
[[alternative HTML version deleted]]
______________________________________________
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.