Sample size estimation for parallel design [Power / Sample Size]

posted by Nav Coelho – 2007-07-20 18:14 (6353 d 05:13 ago) – Posting: # 916
Views: 28,047

Dear all,

I have data from a parallel pilot study and am using that to estimate the sample size for a pivotal study. The formula that I am using requires an estimate of the inter subject variability which I don't have. I have the total variability (sqrt(MSE)). Is there a way to estimate intersubject variability from a parallel design or would it be correct to use the total variability instead?

Would it be correct to estimate inter-subject var as sd/mean for test and reference separately and then take the average?

And one last question, how correct is it to take 60% of inter subject (calculated as sd/mean) to be the intrasubject variability?

Thanks in Advance!
Nav Coelho

Complete thread:

UA Flag
Activity
 Admin contact
23,336 posts in 4,902 threads, 1,669 registered users;
33 visitors (0 registered, 33 guests [including 10 identified bots]).
Forum time: 22:27 CET (Europe/Vienna)

Every man is fully satisfied that there is such a thing as truth,
or he would not ask any question.    Charles Sanders Peirce

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