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) 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.
