25 Oct 08:22
McSim query
Suhrid Balakrishnan <suhrid <at> paul.rutgers.edu>
2002-10-25 06:22:34 GMT
2002-10-25 06:22:34 GMT
Hi, I'm trying to do some analysis with McSim 4.1 and I'd like to specify priors in a heirarchical fashion exactly as the authors of the software did in their 1996 paper - Bois, F. Y., Gelman, A., Jiang, J., Maszle, D., Zeise, L. and Alexeef, G. (1996). Population toxicokinetics of tetrachloroethylene. Archives of Toxicology 70:347-355. also used in Gelman, A., Bois, F. Y. and Jiang, J. (1996). Physiological pharmacokinetic analysis using population modeling and informative prior distributions. Journal of the American Statistical Association 91:1400-1412. The problem I'm facing is that I see no way to easily incorporate the Lognormal hierarchical prior (mu*, Sigma*) (where mu* and Sigma* are the geometric mean and standard deviations respectively = exp(mu) and exp(Sigma)) with further conditional distributions on mu ~ Normal (M,S) and Sigma as inverse-gamma(a,b) (a, b being the shape and scale parameters, respectively) in the McSim framework. I've tried a number of things including toying with levels, exponents, outputs, scaling etc. and nothing seems to work. What one desires, I presume, is a way to specify the following hierarchical distributions in the simulation file (which the authors used in both references above): Distrib (Sigma_V, InvGamma, 2, 0.1823); Distrib (Mean_V, Normal, 0.1, 1.2); # values are abitrary Distrib (V, TruncLogNormal, exp(Mean_V), exp(Sigma_V), 1e-6,10);(Continue reading)
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