Bioequivalence and Bioavailability Forum • PE at border of the AR: power ≡ 0.05 ?

PE at border of the AR: power ≡ 0.05 ? [Power / Sample Size]

posted by d_labes – Berlin, Germany, 2016-01-13 14:21 (3322 d 02:12 ago) – Posting: # 15824
Views: 12,124

Dear Helmut,

❝ ... When we are considering TOST, it’s simple: Power curves for any sample size intersect at the limits of the BE acceptance range with power exactly 0.05.

Really? Have a look onto this:

power.TOST(CV=0.3, theta0=1.25, n=1002, design="2x3x3")

[1] 0.05

power.TOST(CV=0.3, theta0=1.25, n=102, design="2x3x3")

[1] 0.05

power.TOST(CV=0.3, theta0=1.25, n=30, design="2x3x3")

[1] 0.0499998

power.TOST(CV=0.3, theta0=1.25, n=18, design="2x3x3")

[1] 0.0497759

power.TOST(CV=0.3, theta0=1.25, n=15, design="2x3x3")

[1] 0.04881418

power.TOST(CV=0.3, theta0=1.25, n=12, design="2x3x3")

[1] 0.04446453

Seems your statement "... any sample size ... with power exactly 0.05." is not thoroughly correct :cool:

.
Think about "The TOST procedure can be quite conservative, i.e. the achieved Type I error rate may be lower than the nominal 0.05 significance level"¹ or "TOST is not the most powerful test".

(Count up: post 993)

¹Jones B, Kenward MG.
Design and analysis of cross-over trials.
Boca Raton: Chapman & Hall/CRC; 3^rd ed 2014
Chapter 13, Introduction

(Count up: post 993)

—
Regards,

Detlew

Complete thread:

Post hoc Power Jay 2016-01-08 06:49 [Power / Sample Size]
- Post hoc Power ElMaestro 2016-01-08 15:07
- Post hoc Power Helmut 2016-01-09 14:21
  - Post hoc Power Jay 2016-01-11 10:59
    - PE outside the acceptance range Helmut 2016-01-11 14:02
      - PE outside the acceptance range Jay 2016-01-13 08:24
        
        Power for PE outside the acceptance range d_labes 2016-01-13 11:59
        PE at border of the AR: power ≡ 0.05 Helmut 2016-01-13 12:38
        
        PE at border of the AR: power ≡ 0.05 ?d_labes 2016-01-13 13:21
        
        PE at border of the AR: power ≤0.05! Helmut 2016-01-14 01:29
        
        UMP - uniformly more powerful test d_labes 2016-01-15 20:08
        PE at border of the AR: power ≤0.05! zizou 2016-01-24 22:12
        
        Smoothing artifact Helmut 2016-01-25 14:15