Sample size calculation in medical studies.
Optimum sample size is an essential component of any research. The main purpose of the sample size calculation is to determine the number of samples needed to detect significant changes in clinical parameters, treatment effects or associations after data gathering. It is not uncommon for studies to be underpowered and thereby fail to detect the existing treatment effects due to inadequate sample size. In this paper, we explain briefly the basic principles of sample size calculations in medical studies.
Department of Biostatistics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Mohamad Amin
MA
Pourhoseingholi
Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Mohsen
M
Vahedi
Alborz University of Medical Sciences, Karaj, Iran.
Mitra
M
Rahimzadeh
Medical studies; Sample size