RE: simulation question

Ethan, Sebastian is right that a non-parametric bootstrap may be suitable for determining the uncertainty in the population parameters. However, I got the impression that you wanted to investigate possible study designs on how informative they are for a future model-based analysis? If you would like to do simulation based on your current best guess of the model parameters (i.e. the point estimates) and you would like to do model based analysis of the future study in isolation, then PsN has another program which is highly efficient and would automatically provide you with summary statistics, without any programming required. This program is called sse for stochastic simulation and estimation: http://psn.sourceforge.net/PDF_docs/sse_userguide.pdf sse would also allow you to investigate the performance of alternative models, e.g. simulation with a two-compartment model and estimation with a one-compartment model, to see if CL can be estimated with good precision and low bias, even from the sparse data of a future study. You need to generate the data sets with the study designs yourself, but the rest is really slick. If you are planning to analyse the new study in conjunction with the currently-available data (i.e. a pooled analysis) there may be some clever way of tweaking sse into evaluating this, but I could not say exactly how to best achieve that. (maybe someone in Uppsala has a suggestion in that case) Best regards Jakob