To obtain a representative sample of new psychology students in a state, a researcher randomly selects 25 colleges and then from each college randomly selects 2 sections of introductory psychology. What sampling technique is this?

• A. Simple random sampling
• B. Multistage sampling
• C. Cluster sampling
• D. Stratified sampling

Answer: (B)

Multistage sampling involves multiple random selection steps to build a sample. In this case, colleges are chosen at random first, creating natural clusters. Then, within each selected college, sections of introductory psychology are randomly chosen, and the students in those sections are studied. This two-step process—randomly selecting units at one level (colleges) and then randomly selecting units within those chosen clusters (sections)—embodies a multistage approach.

This differs from simple random sampling, where every student would be invited to participate in a single random draw from the entire state population, all in one step. It also differs from classic cluster sampling in its pure form, where you would typically survey everyone within the chosen clusters; here you sample within each cluster, which makes it a second stage and thus multistage sampling. Stratified sampling would involve dividing the population into distinct groups and sampling from each group, usually with representation from all groups, which isn’t what’s happening here.