Kudos! [Power / Sample Size]

posted by ElMaestro  – Denmark, 2017-02-05 21:15 (1535 d 06:05 ago) – Posting: # 17016
Views: 21,813

Hi Hötzi,

» Quick & extremely dirty:
» library(PowerTOST)
» 100*power.TOST(alpha=0.5, CV=0.3, theta0=0.95, n=40, theta1=0.8, theta2=1)-1.25
» # [1] 76.57964


I can't follow this, alpha 0.5? Substraction of 1.25% somehow from ... what?

Instead, I propose something along the lines of:

pwrDK222BE=function(alpha, CV, theta0, theta1, theta2, n)
{
  ##power the standard way is P(GMR is below theta2)-P(GMR is below theta1)
  ##and thus we just plug in upper or lower= 1 to get us what we need.
  P= power.TOST(alpha=alpha, CV=CV,
       theta0=theta0, n=n, theta1=theta1, theta2=theta2)
  Plow= power.TOST(alpha=alpha, CV=CV,
        theta0=theta0, n=n, theta1=theta1, theta2=1.0) 
  Phi  =power.TOST(alpha=alpha, CV=CV,
       theta0=theta0, n=n, theta1=1.0, theta2=theta2)
  return(P-Plow-Phi)
}

pwrDK222BE(0.05, 0.3, 0.95, 0.8, 1.25, 40)


[1] 0.7652256

Pass or fail!
ElMaestro

Complete thread:

Activity
 Admin contact
21,419 posts in 4,475 threads, 1,510 registered users;
online 11 (0 registered, 11 guests [including 3 identified bots]).
Forum time: Wednesday 04:20 CEST (Europe/Vienna)

In the Middles Ages the lingua franca of science was Latin.
Nowadays the language of science is bad English.    Anonymous

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5