Bioequivalence and Bioavailability Forum • Power in Diletti's sample size table

Power in Diletti's sample size table [🇷 for BE/BA]

posted by Helmut – Vienna, Austria, 2007-01-02 00:59 (6687 d 06:37 ago) – Posting: # 428
Views: 46,779
(edited on 2007-06-04 12:41)

Dear all,

I performed some comparisons of the code based on Jones/Kenward implemented in R, Diletti's table and results obtained from StudySize (v2.0.1). Quite interesting...

All comparisons were done for CV=20% with ratios of 0.85–1.20. Dilleti reported sample sizes to obtain ≥80% power, calculated odd sample sizes were reported rounded up to the next even number (underlined):


+======+=====+===========+===========+

|  GMR |  n  |  R-code   | StudySize | 

+------+-----+-----------+-----------+

| 0.85 | 134 | 0.8014178 |  0.80167  |

| 0.90 |  38 | 0.8140704 |  0.81536  |

| 0.95 |  20 | 0.8300156 |  0.83451  |

| 1.00 |  16 | 0.8214263 |  0.83305  |

| 1.05 |  18 | 0.7950343 |  0.79996  |

| 1.10 |  32 | 0.8084890 |  0.80992  |

| 1.15 |  72 | 0.8035456 |  0.80411  |

| 1.20 | 294 | 0.8017617 |  0.80182  |

+======+=====+===========+===========+

Power with sample sizes given by Diletti et al. at a GMR of 1.05 were below 80%, calculated both with R and StudySize…

A Monte Carlo Simulation (1000000 runs) for GMR=1.05 and 18 subjects in StudySize resulted in:
Power 0.8006 (95% coverage probability: 0.7998-0.8013).

Differences may be due to the implementation of the algorithm to obtain the value of the noncentral t-distribution by numeric integration...

Maybe somebody of you has access to SAS or software specialized in power analysis (e.g., PASS or nQuery Advisor) and would like to check these results?

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

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Complete thread:

R-Code for Power in 2×2 Cross-over Helmut 2006-12-28 21:33
- Power in Diletti's sample size tableHelmut 2007-01-01 23:59
  - Approximate Power Helmut 2007-01-06 15:17
    - Power Calculation for replicate crossover design mathews 2008-04-03 13:19
      - Power Calculation for replicate crossover design Helmut 2008-04-03 13:49
        
        Power Calculation for replicate crossover design mathews 2008-04-04 13:21
    - Exact Power Helmut 2009-09-25 19:20
      - Exact Power ElMaestro 2009-09-27 23:27
        
        Software validation Helmut 2009-09-28 15:21
        
        All the important answers are here! ElMaestro 2009-09-28 19:12
        
        All the important answers are here! Helmut 2009-09-28 19:52
        
        All the important answers are here! ElMaestro 2009-09-28 20:18
        All the important answers are here! yjlee168 2009-09-28 21:30
        
        All the important answers are here! Helmut 2009-09-28 23:18
        
        42! SASophylistic power oracle d_labes 2009-09-29 13:37
        
        Al Gore Rhythms Helmut 2009-09-29 14:52
        
        Al Gore Rhythms ElMaestro 2009-09-29 18:14
        Al Gore Rhythms yjlee168 2009-09-29 23:55
        
        All the important answers are here! yjlee168 2009-09-29 23:49
- R-Code for Power in 2×2 Cross-over KDA 2019-01-23 04:24
  - R-Code for Power in 2×2 Cross-over Ohlbe 2019-01-27 18:24
- R-Code for Power in 2×2 Cross-over Brus 2021-12-02 15:00
  - R-Code for Power in 2×2 Cross-over ElMaestro 2021-12-02 15:15
    - R-Code for Power in 2×2 Cross-over Helmut 2021-12-02 17:30
  - R-Code for Power in 2×2 Cross-over Helmut 2021-12-02 16:57