Truncated Negative Binomial Model Unexpected Marginal Means
Dear All, Hope all is well! This may be a na?ve question but I am running a hurdle negative binomial model to look at the differences in counts of differing types in different locations. My major interest is the conditional model (ie when counts are above 0). I run the following code: model<-glmmTMB(Count ~ Location*Type + (1 | ID), zi=~Location*Type + (1|ID), data=data, family="truncated_nbinom1",control=glmmTMBControl(optimizer=optim, optArgs=list(method="BFGS"))) var.corr <-VarCorr(model) Conditional model: Groups Name Std.Dev. ID (Intercept) 0.37105 Zero-inflation model: Groups Name Std.Dev. ID (Intercept) 1.3207 emmeans <- emmeans(model, ~ Location*Type, type="response", sigma=0.37105, bias.adjust=TRUE) Location Type response SE df lower.CL upper.CL 0 0 1.117 0.277 631 0.687 1.82 1 0 0.940 0.251 631 0.556 1.59 2 0 0.893 0.266 631 0.498 1.60 0 1 1.325 0.254 631 0.909 1.93 1 1 1.090 0.248 631 0.698 1.70 2 1 1.452 0.300 631 0.967 2.18 Confidence level used: 0.95 Intervals are back-transformed from the log scale Bias adjustment applied based on sigma = 0.37105 However, I?m not sure why the estimated means and confidence intervals will include values below 1 in the conditional model as I anticipated these values would represent the average number of non-zero counts? Is there something I may be doing wrong or not understanding? Thanks in advance for your help! Warm Regards, Alex