Bioequivalence and Bioavailability Forum

Sample size, alpha, beta, beta/2 and that all [General Statistics]

posted by Astea – Russia, 2015-02-07 13:53 (3746 d 05:26 ago) – Posting: # 14387
Views: 9,657

Dear d_labes!

Thanks a lot for your explanations!

❝ don't fiddle too much with the formulas given by Chow, Wang and who ever co-authors. There are many typing errors or hidden, not explained assumptions in the mentioned paper and book.

I naively thought it was one the best books on sample size calculations in clinical trials? Nevertheless I didn't understand why they used z_alpha=1.96 for alpha =0.05...

❝ All other ways are more or less approximations to tackle the problem avoiding the not so easy power calculations. But in the ages where PowerTOST is available there is no need for such approximations :-) .

Yes, your Brainchild is very helpful and irreplaceable!

❝ These attempts are only useful for obtaining a reasonable start value for 'brute force'. As such they are used within PowerTOST.

Does exact Owen's method in general do the same?

❝ Have a look at

❝

Paul Zhang (2003)

❝ "A Simple Formula for Sample Size Calculation in Equivalence Studies"

❝ Journal of Biopharmaceutical Statistics, 13:3, 529-538

❝ to get the formulas used (including z_1-ß or z_1-ß/2 and such things).

Yes, they use the more crafty formula, introducing function varying coefficients before beta...

—
"Being in minority, even a minority of one, did not make you mad"

Complete thread:

MSE calculation jag009 2012-09-13 17:39 [General Statistics]
- MSE calculation from CI of 3x3x3 study d_labes 2012-09-14 09:43
  - Oops! Helmut 2012-09-14 14:31
    - Oops? One or two-tailed? ElMaestro 2012-09-14 15:48
      - One or two-tailed? d_labes 2012-09-17 09:57
        
        One or two-tailed? Astea 2015-02-05 01:20
        
        Sample size, alpha, beta, beta/2 and that all d_labes 2015-02-05 09:31
        
        Sample size, alpha, beta, beta/2 and that allAstea 2015-02-07 12:53
        
        Sample size, alpha, beta, beta/2 and that all d_labes 2015-02-07 16:22
  - MSE calculation from CI of 3x3x3 study jag009 2012-09-24 20:12
    - MSE calculation from CI of 4x4x4 study d_labes 2012-09-25 10:40
      - MSE calculation from CI of 4x4x4 study jag009 2012-09-25 14:59
    - MSE calculation from CI of 3x3x3 study ElMaestro 2015-02-05 12:57

Sample size, alpha, beta, beta/2 and that all [General Sta­tis­tics]

Complete thread:

Sample size, alpha, beta, beta/2 and that all [General Statistics]