Bioequivalence and Bioavailability Forum

Paper, pencil, brain ;-) [Software]

posted by Helmut  – Vienna, Austria, 2009-09-21 20:33 (5749 d 07:39 ago) – Posting: # 4226
Views: 28,299

Dear Yuvraj!

❝ Suppose Geometric Least Square Mean Ratio (T/R)=1.20

❝ Lower Confidence Limit=1.08

❝ Upper Confidence Limit=1.33

❝ Number of Subjects (N)=42

❝ Degrees of Freedom=N-2=40;

❝ TINV(.10,40)=1.683851

So far, so good.

❝ Based on Lower Confidence Limit

❝ CVintra=100*SQRT(EXP(MSresidual)-1)=26%

❝ Based on Upper Confidence Limit

❝ CVintra=100*SQRT(EXP(MSresidual)-1)=29%

I can’t follow you. Which formula were you using?
I got:
MSE based on lower CI and PE: 0.0430666 (CV 21.0%)
MSE based on upper CI and PE: 0.0410446 (CV 20.5%)

Recalculating the CI from the estimated MSEs and the reported PE of 1.20 I got
CI based on lower: 1.06 – 1.36, and
CI based on upper: 1.07 – 1.35,
which is pretty close to the original 1.08 – 1.33…

The actual CV_intra in the study likely was <20.5%, since the reported CI was tighter than both estimates. This discrepancy is due to the limited significant digits of the reported CI and PE. However, since the estimate is conservative you are on the safe side.

❝ I want to confirm,

❝ Whether I am right or wrong?

Probably wrong.

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна! 
Helmut Schütz


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Complete thread:

• Sample Size Calculation sasikumar 2008-04-03 09:19 [Software] 
  • Sample Size Calculation (SAS) Jaime_R 2008-04-03 13:13
  • Sample Size Calculation d_labes 2008-04-23 11:54
    • Sample Size Calculation balakotu 2009-09-07 07:51
    • Sample Size Calculation yuvrajkatkar 2009-09-19 09:24
      • Paper, pencil, brain ;-) Helmut 2009-09-19 11:48
        • Paper, pencil, brain ;-) yuvrajkatkar 2009-09-21 15:10
          • Paper, pencil, brain ;-) Helmut 2009-09-21 15:23
          • Paper, pencil, brain ;-)Helmut 2009-09-21 18:33
            • Paper, pencil, brain ;-) yuvrajkatkar 2009-09-22 16:09
              • No paper, pencil, brain :-( Helmut 2009-09-22 18:22
                • about your lectures yuvrajkatkar 2009-09-23 07:27
                  • About Trust Helmut 2009-09-23 13:50
                    • sample size calculation yuvrajkatkar 2009-10-01 13:33
                      • inter- / intra- / total variance Helmut 2009-10-01 13:52
                        • inter- / intra- / total variance yuvrajkatkar 2009-10-01 17:13
                          • Theta?! Helmut 2009-10-01 17:30
                            • sample size for parallel design yuvrajkatkar 2009-10-03 07:44
                              • Reference? Helmut 2009-10-03 13:46
                                • MSE obtain from Parallel study in WinNonlin yuvrajkatkar 2009-10-09 16:46
                                  • Parallel study in WinNonlin Helmut 2009-10-10 10:51