ABSTRACT
Conventional social science wisdom suggests that a random sample drawn from the study population and selected according to sampling theory will reflect the characteristics of the entire population. Probability sampling refers to sampling in which each unit of the population has an equal or known chance of being selected for study. Simple random sampling is the most common form of probability sampling. There are several methods we might choose to select a simple random sample. Systematic random sampling varies from simple random sampling in that the chosen units are not independent of each other. Non-probability sampling generally is used in exploratory research and by qualitative researchers. Non-probability sampling is very useful and justifiable when the researcher is seeking information in a new area and targets subjects or cases who typify the issue to be studied. Suppose, for example, social workers are working in a respite unit and wish to examine the pressures facing carers of AIDS patients.
