Power for PE outside the acceptance range [Power / Sample Size]

posted by d_labes  – Berlin, Germany, 2016-01-13 12:59 (3322 d 02:47 ago) – Posting: # 15821
Views: 12,118

Dear Jay,

❝ ... But what may be the probable reason for such huge difference between post hoc power of Cmax and AUC.


Simple enough: PE for AUC not outside acceptance range.

For Cmax with PE outside acceptance range you could even have a very large number of subjects in your study without rising your post-hoc power:
library(PowerTOST)
power.TOST(CV=0.2101, theta0=1.278, n=18, design="2x3x3")
[1] 0.02239529
power.TOST(CV=0.2101, theta0=1.278, n=102, design="2x3x3")
[1] 0.005853529
power.TOST(CV=0.2101, theta0=1.278, n=1002, design="2x3x3")
[1] 5.443279e-06

On the contrary power is even decreasing.

The post-hoc power is useless because it is a 1:1 function of the BE test.Full stop.

(Count up: post 992)

Edit: power.TOST() calls changed to partial replicate design after Helmut's post below

Regards,

Detlew

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