Bioequivalence and Bioavailability Forum • power2.TOST()

power2.TOST() [Power / Sample Size]

posted by d_labes – Berlin, Germany, 2014-06-30 11:47 (3971 d 03:05 ago) – Posting: # 13168
Views: 16,993

Dear Helmut!

❝ We could calculate power for n=67 as well:

❝ power.TOST(CV=0.3005, theta0=0.93, n=67, design="2x2")

❝ [1] 0.9011207

That is not recommended. Just to cite the help page of power.TOST:
"The formulas used assume balanced studies, i.e. equal number of subjects in the (sequence) groups."

Use instead:

power2.TOST(CV=0.3005, theta0=0.93, n=c(34,33), design="2x2")

[1] 0.9010638

Depending on the imbalance you may get even power below 90%:

power2.TOST(CV=0.3005, theta0=0.93, n=c(35,32), design="2x2")

[1] 0.9006074

power2.TOST(CV=0.3005, theta0=0.93, n=c(36,31), design="2x2")

[1] 0.8996887

power2.TOST(CV=0.3005, theta0=0.93, n=c(37,30), design="2x2")

[1] 0.8982959

May be I should improve the documentation with a more direct reference to power2.TOST() and a warning.

—
Regards,

Detlew

Complete thread:

Sample size for replicate design partial AUC AngusMcLean 2014-06-25 02:11 [Power / Sample Size]
- sampleN.RSABE() Helmut 2014-06-25 02:53
  - sampleN.RSABE() AngusMcLean 2014-06-25 13:42
    - sampleN.RSABE() Helmut 2014-06-25 15:02
      - sampleN.RSABE() AngusMcLean 2014-06-25 20:05
        
        sampleN.RSABE() Helmut 2014-06-25 21:29
        
        sampleN.RSABE() AngusMcLean 2014-06-27 17:37
      - power2.TOST()d_labes 2014-06-30 09:47
        
        power2.TOST() Helmut 2014-06-30 12:02
        
        power2.TOST() ElMaestro 2014-06-30 12:31
        
        Elementary, my dear Watson! Helmut 2014-06-30 12:43
        
        Elementary, my dear Watson! ElMaestro 2014-06-30 13:07