Bioequivalence and Bioavailability Forum • The mysterious ρ -between or within studies

The mysterious ρ -between or within studies [General Statistics]

posted by d_labes - Berlin, Germany, 2018-02-11 19:36 - Posting: # 18400
Views: 2,970

Dear Nasty!

» So, for ρ=0.8 I get now
»

 > type1error.2TOST(CV=c(0.3, 0.25), n=122, theta1=c(0.8, 0.9),

» +                        theta2=c(1.25, 1/0.9), rho=0.8, details=TRUE)
» 1e+06 simulations. Time consumed (secs)

»    user  system elapsed 

»  979.75   95.18 1115.72 

»   Intersection null P(Type I Error) theta0 #1 theta0 #2
» 1      H_A01 n H_Ca        0.048904 0.8000000  0.953047
» 2      H_A02 n H_Ca        0.049193 1.2500000  1.056122
» 3      H_Aa n H_C01        0.049620 0.9709781  0.900000
» 4      H_Aa n H_C02        0.050024 1.0000000  1.111111
» ...
»

and inflation at 0.050024
Don't forget, that type1error.2TOST() is based on simulations now.
That's mainly because our (authors team of PowerTOST) brain is to small to derive an analytical solution. And simulations have an error. F.i. in setting the seed for the random number generator.

type1error.2TOST(CV=c(0.3, 0.25), n=122, theta1=c(0.8, 0.9), theta2=c(1.25, 1/0.9), rho=0.8, setseed=F)

[K1] 0.049977

In that light 0.050024 is of course not an alpha-inflation. As we know from theory, the IUT principle, the combination of two TOST via and assures alpha<=0.05. Thus interpret the result as 0.05. Full stop

» As I understand estimated from several datasets ρ is "between studies" ρ while in Power2TOST we need to use "within studies ρ".

I myself don't know what ρ or what value of ρ should be used. As I wrote above: It's under discussion now.

Thus if you or somebody else have an opinion or arguments: Give it to me.

—
Regards,

Detlew

Complete thread:

Power and type I adjustment for 222BE when several PK prams considered - Louis52, 2018-02-07 21:04 [General Statistics]
- Power and type I adjustment for 222BE when several PK prams considered - ElMaestro, 2018-02-07 22:37
- Power of two combined TOST - d_labes, 2018-02-08 14:12
  - The mysterious ρ - Helmut, 2018-02-08 21:40
    - ρ ρ ρ your boat - ElMaestro, 2018-02-09 09:58
      - ρ ρ ρ your boat - Helmut, 2018-02-09 19:20
    - ...and a bonus question - ElMaestro, 2018-02-09 11:32
      - ...and a bonus question - Helmut, 2018-02-09 19:43
        
        If u see a BEar don't forget to R oaρ - Astea, 2018-02-09 20:47
        
        package install failed - d_labes, 2018-02-11 13:23
    - The mysterious ρ -between or within studies - d_labes, 2018-02-11 15:57
      - The mysterious ρ -between or within studies - Helmut, 2018-02-11 17:31
        
        The mysterious ρ -between or within studies - d_labes, 2018-02-11 19:21
        
        The mysterious ρ within studies - Helmut, 2018-02-11 22:44
        
        The mysterious ρ within studies - nobody, 2018-02-12 09:08
      - The mysterious ρ -between or within studies - Astea, 2018-02-11 17:34
        
        The mysterious ρ -between or within studies - d_labes, 2018-02-11 19:36
        The mysterious ρ within studies - Helmut, 2018-02-11 22:48
- Power and type I adjustment for 222BE when several PK prams considered - ElMaestro, 2018-02-11 18:43
  - Power and type I adjustment for 222BE when several PK prams considered - nobody, 2018-02-12 09:10
    - reminds me of something - ElMaestro, 2018-02-12 09:18
      - reminds me of something - nobody, 2018-02-12 09:38
        
        Hammer to fall - Astea, 2018-02-12 18:37
        
        Put the sickle to the corn - Helmut, 2018-02-13 01:37
        
        Put the sickle to the corn - Astea, 2018-02-13 08:27
        
        Put the sickle to the corn - Helmut, 2018-02-13 12:45
        
        Put the sickle to the corn - Relaxation, 2018-02-13 10:37
        
        multiple units, lag-times - Helmut, 2018-02-13 13:31

Bioequivalence and Bioavailability Forum 07:07 CEST

The mysterious ρ -between or within studies [General Sta­tis­tics]

Complete thread:

The mysterious ρ -between or within studies [General Statistics]