The quality of a piece of research not only stands or falls by the appropriateness of methodology and instrumentation but also by the suitability of the sampling strategy that has been adopted. Questions of sampling arise directly out of the issue of defining the population on which the research will focus. Researcher must take sampling decisions early in the overall planning of a piece of research. After taking decision about the selection and identification of the problem, the objectives and hypotheses of the research study, and the research design (experimental, survey, developmental, descriptive, case study, ethnography etc.), the researcher supposed to take decision about data gathering to realize the objectives of the research study.