A confirmatory randomized controlled trial can be severely underpowered if the variability and/or effect size estimated from a small-scale pilot study is not taken into account in the sample size calc
This is the Power calculations used for my thesis, The following calculations gave the Cohan's D (effect size) as well as participants required to achieve a statistical power of 80% for my data analys
In unrestricted or exploratory factor analysis (EFA), there is a wide range of recommendations about the size samples should be to attain correct and stable solutions. In general, however, these recom