Dear ronggui,
There are several approaches you can take, one of which is to fit a GAM and
simply look to see whether the relationships appear linear on the logit
scale. As well, you could compare the fit of the GAM with semiparametric
models in which each smooth term in turn is replaced by a
as agresti(2002) points out that we had better to screen the data to see if the
the logit(pi) and the predictor has linear realtionship in logistic
regressin.and i find some materials in MASS and the refernce of s-plus.but it
is a bit simple and i can not exactly master the means to assess
I am a little confused about what you asked.
If you want to assess the linearity in logistic regression, why do you
want to use GAM instead of GLM?
As far as I understand, GAM is used to capture nonlinearity rather linearity.
Am I right here?
On Apr 1, 2005 10:19 PM, ronggui [EMAIL
maybe the idea is simle,but the details is beyond me.you are right,gam can
capture the non-linearity.but if the results from gam shows little evidence on
on-linearity,then we can assume linearity exists. am i right?
from agresti(2002):
...
Before fitting the model and making such
