R help - Jul 2008 - logistic regreesion and score test

Hi guys,

Here I have a dataset with 800 positive samples and 800 negative ones
looking like this

y x1 x2
1 0 1
-1 1 1
......
I want to build a logistic regression model with y as the dependent
variable, x1 and x2 as the independent variables (logit(y)=b0+ b1*x1
+b2*x2.). Then I want to compare this model with the NULL model which is
b1=0 and b2=0 using a score test. With the P value I get from score test, I
can then tell whether the two independent variables are significant related
with y.

Does anyone know how to do that in R? Which function should I use? Many many
thanks,

--Jerry

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?? wrote:
> Hi guys,
> 
> Here I have a dataset with 800 positive samples and 800 negative ones
> looking like this
> 
> y x1 x2
> 1 0 1
> -1 1 1
> ......
> I want to build a logistic regression model with y as the dependent
> variable, x1 and x2 as the independent variables (logit(y)=b0+ b1*x1
> +b2*x2.). Then I want to compare this model with the NULL model which is
> b1=0 and b2=0 using a score test. With the P value I get from score test, I
> can then tell whether the two independent variables are significant related
> with y.
> 
> Does anyone know how to do that in R? Which function should I use? Many
many
> thanks,
> 
> --Jerry
Score tests are good but so are likelihood ratio tests and sometimes 
Wald tests.  The latter two are easy to do with glm or the lrm and anova 
functions in the Design package.

Frank
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University