Factors Affecting The Determination Of Sample Size

To study any phenomenon or population from scientific research and data collection sight of view Sampling method or Complete survey may be needed. Sampling is preferred because of it is distinctive characteristics, including, reduction of time and costs. The results can be generalized and applied accurately to population without needing total survey. Some factors that may affect sampling method, include the level of precision, the level of confidence, the degree of variability in the attributes being measured, and the variance. The reliability of sample information depends mainly on the sampling method, the variability of population, the sample size, and the population size. With these four variable features, there are many situations in which different proposed sampling schemes can be employed. Sample size calculations at the planning stage ensure that there are sufficient amount of subjects for providing accurate and reliable assessment. If a large sample size is needed we may decrease the standard error or increase the proportion. Z-test for two tails may be used when large sample size is required. On using variance the sample size follows the Poisson distribution.