# How to set the variances of Priors to THETAS in \$PRIORS

From: Rong Chen <rongchenchn>
Date: Mon, 17 Aug 2015 12:10:54 +0000 (UTC)

Dear NMUsers
I'm learning to use PRIOR subroutine in NONMEM.I followed 'NONMEM USERS GUI=
DE INTRODUCTION TO NONMEM 7.3.0(P77)' and it says:    T=
he \$OMEGA records list the variances, in order, the following:
NETAxNETA of initial OMEGAS
NTHPxNTHP of variances of P=
riors to THETAS
NETPxNETP of priors to OMEG=
AS, matching the block pattern of the initial OMEGAS
And an example is given:    \$OMEGA BLOCK(4)  ; Var=
iance to prior information of THETAS (NTHPxNTHP=4x4 of them).  =
10000 FIX    0.00 10000   =
0.00 0.00 10000    0.00 0.00 0.0 10000Now my ques=
tion is:1) What does 'variance' mean here? Is it the statistical termi=
nology 'variance'? 2)Where can I find this variance?(i.e. 10000 in the matr=
ix above) Perhaps from the output file of previous study? 3)Do the off-diag=
onal elements have to be 0?(This Guide gives multiple examples, where all t=
he off-diagonal elements are set to 0) If not, what values should I set?
I would be very grateful for any guidances and discussion on \$PRIORMany Tha=
nks!Rong Chen
Received on Mon Aug 17 2015 - 08:10:54 EDT

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