can i run an aggregate model with a varcov can you take the clustering effect into account which model is a robust varcov estimator what is the weighting of the exchangeable matrix in epsilon2 is a robust varcov analysis statistically significant is a huber white standard error a robust variance estimator why does the clustering effect of the epsilon2 matrix need to be taken into account in the gee model why does the huber-white sandwich estimator not include school clustering why is the clustering effect not statistically significant can we run a sandwich estimator with a sas model can we take clustering effects into account can an empirical model be used to estimate the clustering effect? how to take clustered student into account in a gee model can you use the sandwich estimator for the epsilon in a gee model? can you use a sandwich estimator in a gee model can we use a robust varcov estimator in the kee model why do i need a robust varcov model when using the robust variance estimator why is the sandwich estimator used when using a robust varcov estimator how to take the cluster effect into account