[R] GLM Quasibinomial - 48 models

Jhope jeanwaijang at gmail.com
Tue Feb 7 10:14:42 CET 2012

I've originally made 48 GLM binomial models and compare the AIC values. But
dispersion was very large:
Example: Residual deviance: 8811.6  on 118  degrees of freedom

 I was suggested to do a quasibinomial afterwards but found that it did not
help the dispersion factor of models and received a warning:

Residual deviance: 3005.7  on  67  degrees of freedom
Number of Fisher Scoring iterations: 13
Warning message:
In summary.glm(qModel48.glm) :
 observations with zero weight not used for calculating dispersion

1) What does this warning message mean? 
2) Is this quasibinomial step necessary or can I just compare the AIC of 48
glm models binomial even though dispersion is very large, well over 2. 


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