Determining Adequate Sample Size for Social Survey Research

Determination of a valid sample size is a fundamental step in research. This paper explains how existing formulas are tied in a single thread by applying the concept of standard error, margin of error, Z and t scores, confidence interval and sampling distribution. Bringing the concept of sample control ratio, we suggest a unified formula which is where I is the sample size, N is the population, t is the t-value at a desired level of probability with df = (N-1) and  is the sample control ratio to be estimated by for continuous variables and for categorical variables where  is the proportion of acceptable error and p is the proportion of presence of an attribute in the population.…