ABSTRACT
In clinical research, during the planning stage of a clinical study, the following questions are of particular interest to the investigators: (i) how many subjects are needed in order to have a desired power for detecting a clinically meaningful difference (e.g., an 80% chance of correctly detecting a clinically meaningful difference), and (ii) what’s the trade-off between costeffectiveness and power if only a small number of subjects are available for the study due to limited budget and/or some medical considerations. To address these questions, a statistical evaluation for sample size calculation is often performed based on some statistical inference of the primary study endpoint with certain assurance. In clinical research, sample size calculation plays an important role for assuring validity, accuracy, reliability, and integrity of the intended clinical study.
