The aim of this paper is to provide an overview of sample size estimations for the most frequent type of group studies that result in continuous, binary and ordered categorical outcomes. In recent ...

Beyond the design, if enrollment slows due to seasonal effects or difficulty finding a niche patient group, a robust design activates a contingency plan that dynamically adjusts site selection based ...

The probability that the null hypothesis will be rejected when it is actually true is called the false positive rate and is determined by the significance level of the test (called alpha which is ...

Power analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required sample size for ...