Log in
RegisterProc Mixed: parallel groups with different variabilities [Design Issues]
Dear John,
Correct.
If this should be read total CV, correct.
But the two groups of subjects (under Test or Reference treatment) would allow the separate estimation of CV(tot.)T and CV(tot.)R (or s2T, s2R in the log domain). And this should be reflected in the overall model.
A Proc GLM ANOVA or your Proc MIXED code assumes equal variabilities aka homogeneous variances, analogous to a t-test assuming equal variances.
But again: My code is a quick shot and may be wrong (or as the Admin of this forum always touts "... should be taken with a grain of salt").
❝ We are looking at a parallel study design whereby two groups of subjects are given either T or R in the 1 study period.
Correct.
❝ Personally I don't see what additional variability(ies) one can extract from a parallel study other than inter-subject CV ...
If this should be read total CV, correct.
But the two groups of subjects (under Test or Reference treatment) would allow the separate estimation of CV(tot.)T and CV(tot.)R (or s2T, s2R in the log domain). And this should be reflected in the overall model.
A Proc GLM ANOVA or your Proc MIXED code assumes equal variabilities aka homogeneous variances, analogous to a t-test assuming equal variances.
But again: My code is a quick shot and may be wrong (or as the Admin of this forum always touts "... should be taken with a grain of salt").
—
Regards,
Detlew
Regards,
Detlew
Complete thread:
- drugs of long half life Ken Peh 2013-03-31 06:43
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- drugs of long half life jag009 2013-04-02 15:17
- drugs of long half life Helmut 2013-04-02 15:34
- drugs of long half life jag009 2013-04-02 16:01
- drugs of long half life Helmut 2013-04-02 16:40
- parallel FDA d_labes 2013-04-04 08:33
- parallel FDA jag009 2013-04-05 18:01
- parallel FDA jag009 2013-04-05 21:10
- random repeated parallel FDA d_labes 2013-04-08 08:29
- Proc Mixed: random repeated parallel FDA jag009 2013-04-08 15:36
- Proc Mixed: parallel groups with different variabilitiesd_labes 2013-04-08 16:41
- Proc Mixed: parallel groups with different variabilities jag009 2013-04-08 20:22
- Proc Mixed: parallel groups with different variabilitiesd_labes 2013-04-08 16:41
- Proc Mixed: random repeated parallel FDA jag009 2013-04-08 15:36
- random repeated parallel FDA d_labes 2013-04-08 08:29
- parallel FDA d_labes 2013-04-04 08:33
- drugs of long half life Helmut 2013-04-02 16:40
- drugs of long half life jag009 2013-04-02 16:01
- drugs of long half life Ken Peh 2013-04-04 15:03
- drugs of long half life jag009 2013-04-05 17:45
- drugs of long half life Helmut 2013-04-02 15:34
- drugs of long half life jag009 2013-04-02 15:17
Ing. Helmut Schütz