I am currently trying to determine the required sample size for an experiment. As I want to use the statistical power concept (for a t-test) to determine the required sample size, I want to specify a power level, significance level and effect size. Using these inputs, e.g. the G*Power tool will allow me to determine the sample size.
A complicating factor is that the results of the analysis will be analyzed using multiple testing. More specifically: 12 tests will be conducted. This caused some doubt on how to specify the inputs for the power analysis:
I am aware of the fact that the significance level needs to be corrected for multiple testing. To determine the sample size, I plan to use a Bonferroni correction. Is my statement correct that the corrected significance level needs to be used as an input for the power analysis?
Is a similar correction required for the power level, i.e. do I have to set a higher power level for the power analysis to obtain a particular power over all 12 tests?
Thank you for the input.