using identity link for binomial familly with glm
On Tue, 31 Jul 2001, Stephane Dupas wrote:
-- Error in binomial(link = "identity") : identity link not available for binomial family, available links are "logit", "probbbit", "cloglog" and "log" Hi, I have a question, dealing with this error response. I'm trying to make anova on percentages. The variablethat has a biological significance is actually the percentage itself. Is it really not possible, to test a simple linear probability model with glm, using binomial model and identity link function ? I know it's hard to deal with probability responses out of [0,1] but well... help me ! There is an example of such a linear probability model in Agresti (1997) some software aparently do it
You can do it easily: use a quasi model. quasi(link = "identity", variance = "mu(1-mu)") I believe. You will probably need to specify a good starting value.
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 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._