"stratified sampling"^^ . "0"^^ . . . "00162417-n"^^ . . . . . . "proportional sampling"@en-us . . . "representative sampling"@en-us . "100162417"^^ . "0"^^ . "the population is divided into subpopulations (strata) and random samples are taken of each stratum"@en-us . . "stratified sampling"@en-us . "100153427"@en-us . . "100105545"@en-us .