Bogus PROC MIXED/FDA [Software]

posted by d_labes  – Berlin, Germany, 2010-03-26 10:45 (5926 d 04:18 ago) – Posting: # 4975
Views: 13,423

Grosser Meister!

❝ But how :ponder:?


Thats the question!
Just to cite myself: "I have the strong believe ...". See above.

Without really understanding the AlGore rhythms for REML as a "statistical amateur" (stolen from Helmut :cool:) the overall variance matrix, which is part of the likelihood, which is maximised or equivalently -log likelihood is minimised ... :blahblah: is

V= Z*G*Zt + R

where the intra-individual variance parameter go into R matrix and the inter-individual go into G. There is no possibility within Proc MIXED, and I suppose also in other real mixed model software, to parameterize a interdependence between both. And such an interdependence we have.

Just a short outline (according to McNally's paper, citation above):
From the values of Test -> total variability of T = var(between-T)+var(within-T)
From the subject mean values of Ref -> total variability of R = var(between-R)+var(within-R)/2
From R-R -> within variability of R = var(within-R)
From T-R -> var(diff) = var(SxF) + var(within-T) + 0.5*var(within-R)

red: not separable between and within terms because of
var(SxF)=var(between-T)+var(between-R)-2*cov(between-T,between-R)

Thats the basis of my strong believe.

Regards,

Detlew

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