probability sampling

probability sampling

any process in which a sample of participants or cases is chosen from a larger group in such a way that each one has a known (or calculable) likelihood of being included. This requires a well-defined population and an objective selection procedure, as in random sampling. Additionally, all members of the population must have some (i.e., nonzero) chance of being selected, although this probability need not be the same for all individuals. Compare nonprobability sampling.