A cluster sample is a sampling method where the population is divided into groups, or clusters, and a random sample of these clusters is selected. All members of the chosen clusters are then included in the sample.
Simple Random Sample: A sampling method where every member of the population has an equal chance of being selected.
Stratified Sample: A sampling method that divides the population into subgroups (strata) and takes a random sample from each subgroup.
Systematic Sample: A sampling method where every nth member of a population is selected after a random starting point.