coefficient of logistic regression
John Fox wrote:
Dear Ahmet, Sorry for the slow response, but I've been busy all today, coincidentally teaching a workshop on logistic regression. Tom Blackwell sent you a useful suggestion for interpreting coefficients on the odds scale. If you want to trace out the partial relationship of the fitted probability of response to a particular predictor holding others constant, you can set the other predictors to typical values and let the predictor in question vary over its range, transforming the fitted log-odds to the probability scale. You may be interested in my effects package (on CRAN or at <http://socserv.socsci.mcmaster.ca/jfox/Misc/effects/index.html>), which makes these kinds of displays for linear and generalized-linear models, including those with interactions. Regards, John At 03:06 PM 6/3/2003 +0300, orkun wrote:
John Fox wrote:
At 11:54 AM 6/3/2003 +0300, orkun wrote:
in logistic regression, I want to know that it is possible to get probability values of each predictors by using following formula for each predictor one by one (keeping constant the others) <<< exp(coef)/(1+exp(coef)) >>>
Dear Ahmet, This will almost surely give you nonsense, since it produces a fitted probability ignoring the constant in the model (assuming that there is one), setting other predictors to 0 and the predictor in question to 1. What is it that you want to do? I hope that this helps, John
thank you Say, I just want to find each predictor's particular effect on dependent variables. Actual model is to prepare landslide susceptibility map on GIS. So I want to know what the effect as probability value comes from each predictor. For instane what is the effect of slope on landslide susceptibility. Should I keep others constant ? kind regards
----------------------------------------------------- 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 -----------------------------------------------------
Dear Mr. Fox
thank you very much all.
Because of related to your answer. I ask you directly if you don't mind
I studied several ways after my email.
I wonder whether pgeo<-predict.glm(glm.ob,type="terms")
gives same result with probability value I asked before.
I tried on it. But it gives "Error in rep(1/n,n) %*%
model.matrix(object): non conformable
arguments" .
By the way , your teaching notes is available on the internet ?
cordially
can y
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