Wondering how many people in the United States have a smartphone? If you poll 20 people on the street, your survey won’t be representative of the entire American population. But if you just want to ...

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 ...

Back in the day, we learned in statistics that you need a sample size of at least 2% of the size of population to make statistically significant conclusions about the behavior of the population. In ...

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 ...