Since I found an insignificant result, I performed a power calculation in G*Power. But I am not entirely sure if I input the right number in some fields. My design is a 2(between Ss) x 2(between Ss) design, so I have 2 variables, 4 different conditions (20 participants in each one). I ran an univariate test in SPSS.
- Is the SD sigma within each group the averaged SD of the 4 conditions?
- is the number of measurement 4?
- I am not sure what to out in Corr among rep measures, so I ran a bivariate correlation test in SPSS (Pearson, 1-tailed). I found the correlation between the 2 variables is 0. So I put 0 there. Am I correct?
by the way, have anyone read an experiment in which researchers found an insignificant result because the power is not enough (due to small sample size). I want to read an article like this since I am having the exactly same situation now.
Thank you so much! :)