Avoid partial replicate designs, pleeeze! [🇷 for BE/BA]

posted by ElMaestro  – Denmark, 2020-07-11 16:43 (2166 d 14:23 ago) – Posting: # 21673
Views: 40,386

Hi again,

it is rather experimental.
I do not have a level of understanding that allows me to use V=ZGZt+R,
so I will be constructing V directly from the data listing without the intermediary Z and G. I do not wish to get bogged down by the various aspects of covariance matrices; if CSH does not pan out well in SAS then it is an implenetation or convergence issue only, it is not because CSH is irrelevant. CSH is for all practical purposes the covariance matrix that makes sense, which means we have:
A variance for T (combined within and between)
A variance for within-R
A variance for between-R


Hessian, positive definite, etc.. all this comes down to the details of SAS's or WinNonlin's optimiser. I am playing around with optim in R (BFGS, L-BFGS-B bounded, and Nelder-Mead) and with one of my own making.
—
Pass or fail!
ElMaestro

Complete thread:

UA Flag
Activity
 Admin contact
23,654 posts in 4,992 threads, 1,570 registered users;
155 visitors (0 registered, 155 guests [including 13 identified bots]).
Forum time: 07:06 CEST (Europe/Vienna)

Scientists often have a naïve faith that
if only they could discover enough facts about a problem,
these facts would somehow arrange themselves
in a compelling and true solution.    Theodosius Dobzhansky

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5