Inline. -- Bert Bert Gunter
"The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Aug 31, 2016 at 10:03 AM, Anderson Eduardo <anderson...@gmail.com> wrote: > Hello > > I have started to work with GLM and I am facing the following problem: > > If I take: > > y = c(0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0) > x = 1:18 > > model = y ~x + I(x^2) > GLM = glm(model, family=binamial(link = logit)) > > And use the parameters returned by GLM to contruct an equation for the > regression model: > > model.eq = -0.446078 + 0.267673*x - 0.014577*I(x^2) ## Not what I got with your data. I got: Coefficients: (Intercept) x I(x^2) -18.5750 5.0403 -0.2845 I suspect you had some other x,y variables lying around when you defined your model. -- Bert > > And backtransform it from the logit to the natural scale (using the inverse > link-function for this case): > > model.proj = exp(model.eq)/(1+exp(model.eq)) > > the plot for model.proj~x is not the same of the plot for fitted(GLM)~x > (see the output attached). > > Why is this happening? Can someone help me? > > Regards, > > Anderson Eduardo > > -- > Anderson A. Eduardo > ------------------------------------------------------------------------------ > Lattes <http://lattes.cnpq.br/3826166230581311> | Researcher ID > <http://orcid.org/0000-0001-8045-8043> | Google Acadêmico > <https://scholar.google.com.br/citations?user=oOUjq9IAAAAJ&hl=pt-BR> | Site > <http://andersonaireseduardo.xpg.uol.com.br/> > ------------------------------------------------------------------------------ > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.