Bioequivalence and Bioavailability Forum • Parallel groups in bear

Parallel groups in bear - CIs [🇷 for BE/BA]

posted by ElMaestro – Denmark, 2010-04-22 23:47 (5539 d 04:09 ago) – Posting: # 5188
Views: 62,702

Dear d_labes,

❝ Seems to me as there is something wrong with the random part.

OK, then here's a potential theory:
if we do lme(lnAUC0t ~ drug, random=~1|subj, data=TotalData, method="REML" )
on a dataset where we have parallel non-replicated groups (one observation per subject) then R might be trying to actually fit the error sigma² on the diagonal of V (R matrix), and for ZGZ^t possibly ending up with a subject sigma² on the diagonal. Since there is only one observation per subject, I guess this would amount to a V with error-sigma² plus subject-sigma² on the diagonal.
Now error-sigma² plus subject-sigma² can be estimated, but the individual components cannot (would explain anomalies, at least). We would effectively only be working with a single sigma².
In this case, I would be inclined to imagine that the error-sigma² plus subject-sigma² would equal the residual error from an anova on lm(lnAUC0t~drug) or something like that.

Best regards
EM.

—
Pass or fail!
ElMaestro

Complete thread:

Parallel bears meeting at random in infinity d_labes 2010-04-22 11:43
- Parallel bears meeting at random in infinity ElMaestro 2010-04-22 12:53
  - Parallel groups in bear - CIs d_labes 2010-04-22 14:00
    - Parallel groups in bear - CIsElMaestro 2010-04-22 21:47
      - Parallel groups in bear - CIs d_labes 2010-04-23 09:09
    - Parallel groups in bear - CIs yjlee168 2010-04-25 23:29
- Parallel bears meeting at random in infinity yjlee168 2010-04-22 23:09
  - Modelling Parallel bears d_labes 2010-04-23 09:12
    - Modelling Parallel bears yjlee168 2010-04-23 21:14
      - Validating vs. WinNonlin... Helmut 2010-04-24 00:28
        
        Validating vs. WinNonlin... yjlee168 2010-04-24 19:36
        Validating vs. WinNonlin... yjlee168 2010-04-26 00:09
        
        Validating vs. WinNonlin... Helmut 2010-04-26 01:29
        
        WNL in replicate BE yjlee168 2010-04-26 08:59
        
        WNL in replicate BE Helmut 2010-04-26 16:15
      - Modelling Parallel bears yjlee168 2010-04-25 19:34
        
        Modelling Parallel bears ElMaestro 2010-04-25 20:40
        Dataset Helmut 2010-04-25 22:38
        
        Dataset yjlee168 2010-04-25 22:44
        
        Dataset Helmut 2010-04-26 01:13
        
        Dataset yjlee168 2010-04-26 08:16
        
        NCA → Statistical analysis for parallel study Helmut 2010-04-26 13:12
        
        NCA → Statistical analysis for parallel study yjlee168 2010-04-26 18:43
        
        dilemma yjlee168 2010-04-26 08:41
        Equal variances d_labes 2010-04-26 09:04
        
        Equal variances yjlee168 2010-04-26 09:22
        
        GLM = Equal variances d_labes 2010-04-26 13:29
        
        GLM = Equal variances Helmut 2010-04-26 14:45
        
        I'm a believer d_labes 2010-04-26 15:58
        
        I'm a believer Helmut 2010-04-26 16:31
        
        Equal variances Helmut 2010-04-26 12:55
        
        gls() for unequal variances? d_labes 2010-04-26 16:36
        
        gls() for unequal variances? Helmut 2010-04-26 17:00
        Sims Helmut 2010-04-27 01:36
        
        Sandwich - Simsalabim d_labes 2010-04-28 10:58
        
        Sandwich - Simsalabim Helmut 2010-04-28 14:19
        parametrization of R function rlnorm martin 2010-05-02 18:22
        
        Mean of log-normal d_labes 2010-05-03 16:22
        parametrization of R function rlnorm ElMaestro 2013-07-26 21:42
        
        Martin‽ Helmut 2013-07-28 02:01