Open issues [R for BE/BA]

posted by PharmCat  – Russia, 2020-08-07 11:29 (254 d 14:01 ago) – Posting: # 21830
Views: 7,709

Hi ElMaestro!

I thought you asked about p, sorry :)

» Xi is the design matrix for fixed effects for the i'th subject.
» Thus is has a rank of max 3 and never more. This means we can at most use it to work with three parameter estimates. For example an intercept, a treatment effect, a period effect (within any given subject).

I think Xi is not shuld be full-rank design matrix. It is just part of X for subject i. Moreover all Xi should be the same width (num of columns) for Σ(Xi'V-1Xi). Also with (yi - Xi*β) you get residuals ri (col num of Xi should be equal length β).
There is not very accurate description in Gurka's paper, but it provide good concept.
If you check, it should work.

Complete thread:

 Admin contact
21,419 posts in 4,475 threads, 1,509 registered users;
online 14 (0 registered, 14 guests [including 3 identified bots]).
Forum time: Monday 01:31 CEST (Europe/Vienna)

There is one certainty in drug development
and statistics that one can depend on:
the data are always late.    Scott Patterson and Byron Jones

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