Research Methodology Part 5 : Sampling and Sampling Strategy or Plan

Abstract(s)

This tutorial material in PowerPoint is the fifth of an eleven-part package designed and used regularly for teaching research methodology particularly to post-graduate students and research scholars of Library and Information Science. This part discusses ‘sample and sampling design’ as an important step in research design methodology. The tutorial presents the need for sampling, basic concepts of sampling, sampling theory and sampling distribution. Important steps in sampling, criteria for selecting a sampling procedure, various sampling strategy/ design and ways of computing sampling errors are described with illustrations and examples. Sampling is one of the important steps in research which is often over looked by stating that some random or non-random sample design has been adopted. Development of proper sampling frame and a definite plan for obtaining a sample from the sampling frame based on random sample design (rather than nonrandom design) is necessary. A good sampling design should be economically viable, able to control systematic bias, lead to optimum size of sample but small sampling error, enable results be applied to the universe in general with a reasonable level of confidence (ie., reliability) and the resulting sample should be adequate, truly representative and similar to population. In practice many researchers overlook the appropriate probability random design for choosing sample and determination of sample size. Non-probability sampling like convenience sampling and purposive sampling should not be thought of unless it is for a qualitative research. Right type of simple or complex random design has to be chosen for sampling. The sample size depends on nature of units, population and study, number of variables, groups and sub-groups to be studied, intended depth of analysis, precision and reliability of results required, level of expected non- response, size of questionnaire and population and available resources. It should be noted that the size of sample is more important than the proportion of the population represented by sample. There are well established statistical techniques to determine the sample size. Earlier parts are accessible at: Part 1: http://eprints.rclis.org/archive/00009276/ Part 2: http://eprints.rclis.org/archive/00009533/ Part 3: http://eprints.rclis.org/archive/00010170/ Part 4: http://eprints.rclis.org/archive/00010879/