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Thread: Power calculation

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    Re: Power calculation





    I agree that the 27% versus 53% is much more useful. Just be sure you understand what it is telling you -- with 55 subjects per group, you can only reliably detect this rather large difference. As you saw, even for a difference as big as 27% versus 40%, you have too little power. Hopefully you can use these results to begin making some serious plans for future studies. Right NOW -- figure out what effect size (say, what difference from 27% or 40% you would like to be able to detect reliably. Get an appropriate sample size. Might be 100, or 150. Then store that data for the next time you want to do this analysis, say 2 years from now, and your pre-planning will give you enough subjects to do a useful test at that time.
    Last edited by EdGr; 07-16-2016 at 11:32 AM. Reason: typo

  2. The Following User Says Thank You to EdGr For This Useful Post:

    GretaGarbo (07-16-2016)

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