Determine the availability of subjects for your research. Setting rigid qualifications for study subjects reduces the sample size due to the limited number of people meeting your standards.

Course TopicsPower 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 ...

We derive an explicit form for power/sample size calculation based on these two tests. A number of simulation studies have been used to illustrate the efficiency of the tests for the case-cohort ...