Re: [R] logit GLM without intercept

From: <gorgasal_at_gmx.de>
Date: Tue, 22 Apr 2008 17:04:24 +0200


Hi Robert,

you can exclude the intercept by including "-1" in the formula:

value <- as.numeric(runif(20)<.4)
ppm <- rnorm(20)

glm(value~ppm-1,family=binomial)

HTH
Stephan

> Dear Statisticians,
>
> I would like to analyse my data with a GLM with binomial error distribution
> and logit link function. The point is that I want a model fitted without
> intercept, i.e. the fitted curve should start at y=0.5 for x=0.
>
> I tried it with the following code:
>
> glm(value~0+ppm, binomial)
>
> Does this code yield the correct model or is there another possibility? I?d
> appreciate it very much if you could help me out with this. I attached some
> example data.
>
> Thanks & all the best
>
> Robert

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Received on Tue 22 Apr 2008 - 15:57:18 GMT

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