Hi Amy,
I personally have love using the PS power and sample size calculator
(http://biostat.mc.vanderbilt.edu/wiki/Main/PowerSampleSize) for years. It's
many options to choose from based on your needs. Of course there are also a
lot online, but I think this one has been available for so long that we can
trust in the underlying calculations.
Of course, when in doubt, it always helps to run the numbers by a
statistician for confirmation.
Hope this helps.
Ahmed
-----Original Message-----
From: Evidence based health (EBH)
[mailto:[log in to unmask]] On Behalf Of Amy Price
Sent: Wednesday, January 23, 2013 10:21 PM
To: [log in to unmask]
Subject: Sample size for internet RCT diet intervention
Dear all,
Does anyone have a good resource to determine a good sample size for an
internet based diet internet intervention.
Best `regards,
Amy
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