Vous avez cherché: cluster sampling (Anglais - Allemand)

cluster sampling
klumpenstichprobe

post cluster sampling
post-cluster-auswahl

sampling
stichprobenverfahren

in two-stage cluster sampling, a random sampling technique is applied to the elements from each of the selected clusters...
die elemente der klumpen werden dann allerdings vollständig erfasst (alle schüler der ausgewählten schulen werden befragt).

each member state must have a sampling plan, based on a multistage cluster design:
jeder mitgliedstaat muss einen probenahmeplan vorweisen, der auf einem mehrstufigen clusterkonzept beruht:

they were selected using a cluster-random sampling method and were randomly assigned to the intervention (n=40) and control groups (n=40).
they were selected using a cluster-random sampling method and were randomly assigned to the intervention (n=40) and control groups (n=40).