In a village with 500 households divided into 50 clusters, a researcher randomly selects 10 clusters and surveys all households within those clusters. This sampling method is called:
- A Systematic random sampling
- B Stratified random sampling
- C Cluster sampling ✓
- D Quota sampling
Correct answer: C. Cluster sampling
Explanation
Cluster sampling involves dividing the population into naturally occurring groups (clusters) and then randomly selecting entire clusters for study. It is cost-effective for geographically dispersed populations but has lower statistical efficiency compared to simple random sampling. The WHO EPI coverage survey uses a 30×7 cluster sampling methodology to assess immunization coverage.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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