Dear all, I'm trying reproduce an example of bioassays Yielding Concentration-Mortality Data particularly control - adjustment model from book Bioassay of Entomopathogenic Microbes and Nematodes chapter 7 with R.
I used glm with family=binomial and link=probit, but I do not know how to implement parameter gamma (control mortality - mortality of the untreated control insect in this exaple) into model formula. Model in book: pi(x)=gamma+(1-gamma)F(alpha+beta log(x)) F....cumulative probability distribution function data: x=concentration n=number of insect at each run y=number of death among n in given batch run at given concentration Xmat<-data.frame(x=rep(c(0.01,0.1,1,10,100),2),n=rep(100,10),y=c(19,20,21,45,80,25,25,27,56,91)) Reults from book (obtained from SAS) are intercept -1.6597 , beta =0.5586, control mortality --- gamma =0.2172 Thanks for any advice. Michael --- Odchoz� zpr�va neobsahuje viry. Zkontrolov�no antivirov�m syst�mem AVG (http://www.grisoft.cz). Verze: 6.0.530 / Virov� b�ze: 325 - datum vyd�n�: 22.10.2003 [[alternative HTML version deleted]] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
