Re: [NMusers] bootstrap

From: Niurys.CS <amaranthfan_at_gmail.com>
Date: Sat, 11 May 2019 09:33:04 -0500

Dear Nick and Bill,

Thank you for your answers, and please apologize me for din´t give you
information about my model.
 I share with you part of my code as well as some results. My model
corresponds to QSS with constant Rtot approximation of TMDD The
parameter estimates obtained with this model are pausible, and are
similar to prevuios study (Rodriguez L et al, 2015). The GOF and VPC
look good.
The FLAGS correspond to some outliers based on DV of some IDs
(concentration of product). So, I don´t know if excluding these
values, the boostrap will work correctly.

;----------------------------------
$DATA data_19.csv IGNORE=_at_
IGNORE=(FLAG.EQ.2) IGNORE=(FLAG.EQ.3)

;----------------------------------
$SUBROUTINE ADVAN13 TOL=9
;----------------------------------
$MODEL COMP=(CENTRAL) COMP=(PERIPH1) COMP(PERIPH2)
;----------------------------------
$PK

TVCL= THETA(1)
TVV1= THETA(2)
TVQ = THETA(3)
TVV2 = THETA (4)
TVKSS = THETA (5)
TVKINT = THETA (6)
IF(DOS.EQ.50) TVRMAX= 0.175
IF(DOS.GT.50)TVRMAX=THETA(7)

CL = TVCL;*EXP(ETA(1))
V1 = TVV1*EXP(ETA(1))
Q = TVQ*EXP(ETA(2))
V2 = TVV2*EXP(ETA(3))
KSS = TVKSS;*EXP(ETA(4))
KINT = TVKINT
RMAX = TVRMAX

K = CL/V1
K12 = Q/V1
K21 = Q/V2
S1 = V1


Thank you,

Niurys

2019-05-10 12:45 GMT-05:00, Bill Denney <wdenney_at_humanpredictions.com>:
> Hi Niurys,
>
> The simplest method to ensure a good bootstrap is often to simplify the
> data
> file by removing rows that should not be used for the modeling before
> running the bootstrap. Notably, if you exclude an entire subject either
> based on the ID column or another column, usually the boostrap will not
> work
> correctly.
>
> I believe that most if not all tools generate the bootstrap with new ID
> column values (the ID is given a new sequential value based on sampling
> order). If you exclude an entire subject based on another column, the yo=
u
> will not have the expected number of subjects in the analysis because all
> the bootstrap tools that I know of don't account for exclusions with maki=
ng
> the new data file.
>
> If this doesn't help, giving more info will help. (What tool are you usi=
ng
> for bootstrap? What command line are you running? Can you share the mod=
el
> and a snippet of the data?)
>
> Thanks,
>
> Bill
>
> -----Original Message-----
> From: owner-nmusers_at_globomaxnm.com <owner-nmusers_at_globomaxnm.com> On Beha=
lf
> Of Niurys.CS
> Sent: Friday, May 10, 2019 12:17 PM
> To: nmusers <nmusers_at_globomaxnm.com>
> Subject: [NMusers] bootstrap
>
> Dear nmusers,
>
>
> I have a big doubt. When I used the bootstrap to evaluate my model, I had
> some bugs. In my code I use IGNORE statements based on FLAGS for some
> outliers. I don't know if I remove these IGNORE statements, the bootstrap
> will run well. Can you give me some suggestions???????
>
>
> Regards
>
> Niurys de Castro Suárez
>
> --
>
> MSc Niurys de Castro Suárez
> Profesor Asistente Farmacometría
> Investigador Agregado
> Departamento Farmacia
> Instituto de Farmacia y Alimentos, Universidad de La Habana Cuba "Una
> estrella brilla en la hora de nuestro encuentro"
>


--

MSc Niurys de Castro Suárez
Profesor Asistente Farmacometría
Investigador Agregado
Departamento Farmacia
Instituto de Farmacia y Alimentos, Universidad de La Habana
Cuba
"Una estrella brilla en la hora de nuestro encuentro"

Received on Sat May 11 2019 - 10:33:04 EDT

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