Hi,
I have a matched case-control study with 12 cases and two controls for each case. Evaluating our findings, I want to calculate what our sample size must have been to detect a difference found in another study of a different population.
For the sample size calculation, I intended using the mean values from the other study, but apply the standard deviation from our study.
Mean among cases: 3.14
Mean among controls: 1.58
SD: 1.41
Power 80%, significance level 5%.
How can I go about to find out what sample size we would need in our 1:2 matched study? Can I use any of the calculators found at powerandsamplesize.com, or are there appropriate commands within Stata? Any comments on 2-sided versus 1-sided testing?
Please do not hesitate to request more info if needed. Thank you in advance.
I have a matched case-control study with 12 cases and two controls for each case. Evaluating our findings, I want to calculate what our sample size must have been to detect a difference found in another study of a different population.
For the sample size calculation, I intended using the mean values from the other study, but apply the standard deviation from our study.
Mean among cases: 3.14
Mean among controls: 1.58
SD: 1.41
Power 80%, significance level 5%.
How can I go about to find out what sample size we would need in our 1:2 matched study? Can I use any of the calculators found at powerandsamplesize.com, or are there appropriate commands within Stata? Any comments on 2-sided versus 1-sided testing?
Please do not hesitate to request more info if needed. Thank you in advance.
