[R] Weighted Logistic Regressions using svyglm
ehlers at ucalgary.ca
Tue Oct 20 07:43:14 CEST 2009
> I’m running some logistic regressions and I’ve been trying to include weights
> in the equation. However, when I run the model, I get this warning message:
> Here’s what it says: Warning message: In eval(expr, envir, enclos) :
> non-integer #successes in a binomial glm!
> I think it is because the weights are non-integer values.
> What is a good way to run logistic regressions in R when using non-integer
> I’ve attached the output from the R console of the two different methods
> I've tried.
> The first regression is unweighted. The second regression includes the
> weights in glm. The third regression includes the weights in svyglm.
> However, despite using the same weights, I get contradicting results.
> Perhaps I am misunderstanding how to use one or both of these functions.
You might be misunderstanding the use of weights in a binomial glm.
An excerpt from ?glm:
"For a binomial GLM prior weights are used to give
the _number of trials_ when the response is the
_proportion of successes_"
> I'd appreciate any help you can provide.
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