Representative

A sample is said to be representative when it has been generated via a representative draw, meaning that each individual in the population had a non-zero probability of being selected. Representativeness relates to the sample and not to a unit of the population. It is not synonymous with a proportional sample or a "reduced model" of the population studied. In survey theory, it has been demonstrated that an optimal sampling strategy consists of organising the sample according to the variables that are most correlated to the subject of the study.