Which approach divides the population into groups and then selects a sample of the groups?

Which approach divides the population into groups and then selects a sample of the groups?

• A. Cluster Random Sample
• B. Stratified Random Sample
• C. Probability Sample
• D. Non-Probability Sampling

Answer: (A)

Dividing the population into natural groups and then sampling those groups describes cluster sampling. In this approach you first break the population into clusters—such as geographic areas, schools, or clinics—and then randomly select a subset of those clusters. Data are collected from all individuals within the chosen clusters (one-stage) or from a sample of individuals within those clusters (two-stage). This design is especially efficient when the population is large or spread out, reducing travel and administration costs. Because the clusters are chosen randomly, it falls under probability sampling. It contrasts with stratified sampling, where you also form groups, but you sample individuals from every group to ensure representation across subgroups. An example: to study student experience nationwide, you might divide by schools, randomly pick some schools, and survey all students in those schools.

Dividing the population into natural groups and then sampling those groups describes cluster sampling. In this approach you first break the population into clusters—such as geographic areas, schools, or clinics—and then randomly select a subset of those clusters. Data are collected from all individuals within the chosen clusters (one-stage) or from a sample of individuals within those clusters (two-stage). This design is especially efficient when the population is large or spread out, reducing travel and administration costs. Because the clusters are chosen randomly, it falls under probability sampling. It contrasts with stratified sampling, where you also form groups, but you sample individuals from every group to ensure representation across subgroups. An example: to study student experience nationwide, you might divide by schools, randomly pick some schools, and survey all students in those schools.