Prabhaker Mishra
Sanjay Gandhi Postgraduate Institute of Medical Sciences, India
Title: The importance of sample size in research studies
Biography
Biography: Prabhaker Mishra
Abstract
The increasing volume of research by the medical community are also leading numbers of contradictory findings and conclusions. The main reason of the these contradiction are sampling variability and sample size. The differences observed between the groups may represent true difference, but significance level of the same difference is varying from one study to another study due to variation in sample size. Sample size not only affect the level of significance but also affect the power of the study and margin of error. Sample size has no direct relationship with effect size although increasing sample size increases reliability of the effect size detected between the groups. An appropriate sample size, allows the researcher to control the error (Type I & II error). At the time of planning of the study, the researcher must establish a justifiable level of statistical significance, with corresponding power of the study, targeted difference (i.e. effect size) and the variability of the data (for continuous data). The proper planning of sample size can boost the study importance. The aim of this study is to discuss the effect of sample size on level of significance, power of the study and the reliability of the research findings.
