Hi all, I am using the negative binomila glm in MASS. This is my data alled data1: Reps Treats counts HSM1 1 0 21 HSM2 2 0 34 HSM3 3 0 27 PTM1 1 1 32 PTM2 2 1 20 PTM3 3 1 23 I goal is to do a GLM to extract the p-values from Treatment. row. However, I can access the coefficients but not the p-values. On another note, I want to simulate from the null. Is it more appropriate to use: nullmodel <- glm.nb(counts~1,data=data.use) OR should I use: nullmodel <- glm.nb(counts~ Reps,data=data.use) instead? FInally, if I simulate 10 data simulations of the counts, Is this the way to store the p-values? response.sim = simulate(nullmodel,10) for (j in 1:10) { counts.null = response.sim[,j] new.data.mat = data.frame(Reps,Treats,counts.null) new.glm <- glm.nb(counts.null ~ Reps, data = new.data.mat) storage.ps[j] <- 1-pchisq(new.glm$null.deviance,df=new.glm$df.null) } The null is there is no differences between the 2 treatments The alternative is there is a difference between the 2 treatments. Any help is greatly appreciated. -- Thanks, Jim. [[alternative HTML version deleted]]