Simple minded [Software]

posted by Helmut Homepage – Vienna, Austria, 2008-12-12 15:58 (5970 d 12:00 ago) – Posting: # 2916
Views: 31,052

Dear D. Labes,

❝ I guess this is not a problem of SAS. It may be a problem of what we (I) do with it. Fitting an inappropriate? or over-specified? model.


❝ Eventually anybody can fit the underlying model in WINNONLIN or R using REML to see what happens?


❝ I place a bet that then also a fitted value for s2WT is obtained :-P . Maybe it is even correct!?


I fitted Cmax with your modified sequences (because I didn't want to start with incomplete AUC data) in WinNonlin to PBE/IBE and obtained:
SigmaR  0.9999185
SigmaWR 0.4480995
(no SigmaWT!)

❝ (I confabulate: total variability of T: estimable; variability of T-R: estimable and sum of intra-subject variabilities + treatment*subject interaction; intra-subject variability of R: estimable; so ......)


If I run ABE in WinNonlin I'm lost in the options; choosing the defaults (no time to dig into the manual right now...)
fixed:    sequence+treatment+period
random:   subject(treatment) Type: Banded No-Diagonal Factor Analytic(f=2)
repeated: subject(period)   Group: treatment Type: Variance components

I get
Final variance parameter estimates:
           lambda(1,1)_11         0.885348
           lambda(1,2)_11         0.922848
           lambda(2,2)_11         0.213429
Var(period*treatment*subject)_21  0.224827
Var(period*treatment*subject)_22  0.0853385

where according to this post lambda(1,1)_11, lambda(1,2)_11 and lambda(2,2)_11 correspond to SAS' FA(1,1), FA(2,1) and FA(2,2)...

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