glm fit with no intercept
On Fri, 7 Jan 2005, Gudrun Jonasdottir wrote:
I am currently trying to fit a generalized linear model using a binomial with the canonical link. The usual solution is to use the R function glm() in the package "stats". However, I run into problem when I want to fit a glm without an intercept. It is indicated that the solution is in changing
Where is it so indicated?
the function glm.fit (also in "stats"), by specifying intercept=FALSE. I have not been successful in getting any output though. Any suggestion on how to fit a glm with no intercept?
From MASS4:
ldose <- rep(0:5, 2)
numdead <- c(1, 4, 9, 13, 18, 20, 0, 2, 6, 10, 12, 16)
sex <- factor(rep(c("M", "F"), c(6, 6)))
SF <- cbind(numdead, numalive = 20 - numdead)
glm(SF ~ sex+ ldose, family = binomial)
glm(SF ~ sex + ldose - 1, family = binomial) # no intercept
glm(SF ~ ldose - 1, family = binomial) # and not even a factor
Please tell us more of what you have tried.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595