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RegisterFDC Power [Power / Sample Size]
Dear Fabrice,
The impact is also relevant if you don't think extremes. Lets assume CV=0.2 for both ingredients and GMR=0.95 also for both. That gives:
Sample size n=20 with actual power = 0.834680 for each. That lets to an overall power (assuming independence) of only 0.6966907 ~ 70%.
We have to plan for a power of 90% to assure overall power around 80%, which gives n=26, a 30% increase. Not so small IMHO.
❝ The impact would become more relevant if both compounds have a ratio far from unity and/or high variability.
The impact is also relevant if you don't think extremes. Lets assume CV=0.2 for both ingredients and GMR=0.95 also for both. That gives:
Sample size n=20 with actual power = 0.834680 for each. That lets to an overall power (assuming independence) of only 0.6966907 ~ 70%.
We have to plan for a power of 90% to assure overall power around 80%, which gives n=26, a 30% increase. Not so small IMHO.
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Regards,
Detlew
Regards,
Detlew
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