Introduction to sample size calculation

One of the most common reasons why researchers seek help from statistician is sample size calculation. However, despite the common believe that it only involves formula and calculation, researchers often ignore other aspects of research design that leads to proper sample size calculation. In this article, the author outlines basic steps toward sample size calculation. The author also introduces the logic behind sample size calculation for single mean and single proportion in simplified and less intimidating forms to those not statistically inclined.