sample size in bioequivalence studies [Power / Sample Size]

posted by daryazyatina – Ukraine, 2017-08-03 15:46 (2251 d 00:45 ago) – Posting: # 17652
Views: 18,283

Hi, DavidManteigas

❝ For some reason, I can't see the image with the formula that you put on the first post.

Look again at the picture with formula. At first it was not visible, now you can see it.

❝ Within subject standard deviation and within subject CV are different parameters. Nevertheless, I think that this is not the only reason for such a big difference.

I did not write anything about the standard deviation.

❝ "This formula is less conservative than Formula (5), but it may result in a lower actual power than the required. For example, when α = 0.05, σ = 0.3, Δ = 0.2, θ = 0.01 and a required power = 0.80, the sample size from Formula (6) [Formula from Chow] is 17 per sequence, but the actual power obtained by this sample size is only 0.69."

If you looked at the formula I use, you would see in the article that this is another formula Chow. And that's why I do not understand what formula should be used.

❝ So by reading this, I am not sure if Chow formula might be appropriate to calculate sample size for BABE trials. I have just quickly read the article, so I may not be doing a proper analysis. Perhaps dlabes might clarify this, since he is the master that we all should thank for the amazing PowerTOST package :-D

I want to understand how to do it right, just this.;-)

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