Power Calculation

Hi Guys,
Need your help please.
I performed a study- 2 groups (independent) both had 55 patients.
However my supervisor advises that I perform a prospective power calculation
How do I do this? I have had a google but finding it incredibly hard.
Very confused. :(
Thank you
Hi There
I used P=0.05 as statistically significant when I compared the 2 groups, each contained n=55
I performed a re-audit. The original audit had 55 subjects and so when I re-audited I chose 55 subjects, but I think this was failing of the study


New Member
test used for re-audit ie when i compared results obtained within audit 1 to those obtained in audit 2 were pearson chi square but sometimes Fisher Exact for categorical data