Smita Pakhale wrote:
Hi Maria,
But why do you want to use forwards or backwards
methods? These all are 'backward' methods of modeling.
Try using AIC or BIC. BIC is much better than AIC.
And, you do not have to believe me or any one else on
this.
How does that help? BIC gives too much penalization in certain
contexts; both AIC and BIC were designed to compare two pre-specified
models. They were not designed to fix problems of stepwise variable
selection.
Frank
Just make a small data set with a few variables with
known relationship amongst them. With this simulated
data set, use all your modeling methods: backwards,
forwards, AIC, BIC etc and then see which one gives
you a answer closest to the truth. The beauty of using
a simulated dataset is that, you 'know' the truth, as
you are the 'creater' of it!
smita
--- Charilaos Skiadas <[EMAIL PROTECTED]> wrote:
A google search for "logistic regression with
stepwise forward in r"
returns the following post:
https://stat.ethz.ch/pipermail/r-help/2003-December/043645.html
Haris Skiadas
Department of Mathematics and Computer Science
Hanover College
On May 28, 2008, at 7:01 AM, Maria wrote:
Hello,
I am just about to install R and was wondering
about a few things.
I have only worked in Matlab because I wanted to
do a logistic
regression. However Matlab does not do logistic
regression with
stepwiseforward method. Therefore I thought about
testing R. So my
question is
can I do logistic regression with stepwise forward
in R?
Thanks /M
______________________________________________
--
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
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