Will take much more hours still… [R for BE/BA]

posted by Helmut Homepage – Vienna, Austria, 2020-07-13 15:34 (384 d 16:21 ago) – Posting: # 21688
Views: 12,222

Hi ElMaestro,

» I think expressing the G matrix after this fit is a little backward;…

OK, true.

» That SAS and WinNonlin and more do not have a way to make provisions for a solution outside those involving this decomposition, it merely a testament to their development capabilities than to the design itself. If you start defining the the stats model on basis of G and R rather than V then obviously you must create two variance components which are not uniquely estimable, but whose sum is. Therefore, just screw R and G, go directly for V, and present the components without in any way calling them members of G or R - they really aren't when the model is constructed my way.

Yep.

» The 2-trt, 3-seq, 3-per design is good, healthy and appropriate, until now it was just the statistical work on it that has been lagging. The post is an attempt at providing a solution.

Kudos to your work!
I still see no reason to perform a study in one of the partial replicates. Sorry.
What is given as ‘justifications’:Nobody published reference datasets for the mixed-model so far. ;-)
Hence, everybody has to believe in the software. As a starter I would expect the same level of error handling, documentation, :blahblah: like the package replicateBE. Otherwise, assessors would be skeptical.

» The PE will be accessible via the est.b vector. You shuld be able to extract it (difference between first two effects, one good reason to do X without intercept) after the model has converged.

In Section 2:
  Final <- function(Pars) {
    CovM <- Create.CovM(Pars)
    tmp  <- solve(t(X) %*% solve(CovM) %*% X) %*% t(X) %*% solve(CovM) %*% y
    PE   <- exp(as.numeric(tmp["TrtT", ] - tmp["TrtR", ]))
    return(PE)
  }

At the end:
  PE <- Final(res$Estimate)
  cat("PE:", PE, "\n")

Gives:
  PE: 1.372138
In PHX 1.372138 (Patterson/Jones got in SAS 1.37). Great!
TODO: Get the Satterthwaite’s DFs for the CI.

» If you have a dataset that does not readily converge with SAS then I'd be eager to learn if it does in some flavour of my code. :-)

See this post with links to John’s datasets. Maybe there are others.

Dif-tor heh smusma 🖖
Helmut Schütz
[image]

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

Activity
 Admin contact
21,596 posts in 4,516 threads, 1,532 registered users;
online 16 (0 registered, 16 guests [including 7 identified bots]).
Forum time: Monday 07:56 CEST (Europe/Vienna)

Imagine if every Thursday your shoes exploded
if you tied them the usual way.
This happens to us all the time with computers,
and nobody thinks of complaining.    Jef Raskin

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