Bioequivalence and Bioavailability Forum

Power of equality test - 2nd try for the logs [Software]

posted by d_labes  – Berlin, Germany, 2011-11-11 10:55 (4912 d 10:21 ago) – Posting: # 7656
Views: 10,457

Dear Helmut,

seems there is an error / copy and paste mistake in your SEdiff of the full set, log-transformed.
My beasty number cruncher (Proc MIXED) gives:

                              Least Squares Means

Effect       Formulation  Estimate     Error    DF  t Value  Pr > |t|   

 Formulation  Referenc       4.3797   0.05626    22    77.85    <.0001
 Formulation  Test           4.3511   0.05626    22    77.34    <.0001

                       Differences of Least Squares Means

                                                     Standard
  Effect       Formulation  _Formulation  Estimate      Error     DF   t Value

  Formulation  Referenc     Test           0.02865    0.05569     22      0.51

So repeating the power calculations for the Full set, log-transformed :
b  = ln(0.8)/SEdiff = -4.006887 (yicaotings formula)
df = 22
tcrit = qt(0.95,22) = 1.717144...
power = 1 - 1 + 0.9872805 = 0.9872805
Seems reasonable in accordance to WNL I think.

So mystery resolved. Thanx to yicaoting .

Complete thread:

• The secret of WinNonlin's BE's post-hoc Power analysis yicaoting 2011-11-08 14:40 [Software] 
  • The secret of WinNonlin's BE's post-hoc Power analysis yicaoting 2011-11-08 14:55
  • The secret of WinNonlin's BE's post-hoc Power analysis Helmut 2011-11-08 15:06
  • Power of superiority d_labes 2011-11-10 09:49
    • Power of superiority Helmut 2011-11-10 14:39
      • Power of equality d_labes 2011-11-10 16:42
        • Power of equality Helmut 2011-11-10 17:00
          • Power of equality test - 2nd try for the logsd_labes 2011-11-11 09:55
            • Crtl-C/Ctrl-V Helmut 2011-11-11 14:39
        • Power of equality yicaoting 2011-11-12 07:05