If can be transformed to normal you can still
calculate power for a t-test.
You need to decide (in advance) what statistical
test you are actually going to use - power only
applies to a particular question and planned
modality for testing that question. For example if
you wanted to use a Wilcoxon test or Mann-Whitney
U test I could probably help you out (E-mail me off-list).
Best
Aubrey
Aubrey Blumohn
WC>
WC>
WC>
WC> Hi can anyone point me in the right direction
WC> for calculating the required sample size
WC> (based on power etc) for a study but not
WC> assuming that the control and study group are
WC> normally distributed? I’ve found plenty of
WC> calculators that assume normal distribution
WC> and are based on the t-test
WC>
WC>
WC>
WC> Cheers
WC>
WC> Craig
WC>
WC>
WC>
WC> Craig Webster, FRCPath
WC>
WC> Consultant Clinical Scientist
WC>
WC> Birmingham Heartlands Hospital
WC>
WC> Birmingham
WC>
WC> B9 5SS
WC>
WC>
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Regards
Aubrey Blumsohn
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