This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'For which of the following sampling, a Design effect is used? \nSelect and explain. \nA. Simple random sampling, B. Systematic random sampling, C. Cluster random sampling, D. Stratified random sampling', 'role': 'user'}, {'content': 'Answer: C \nExplanation: DESIGN EFFECT\n\nDefinition: Adjustment used in few study/sampling designs to allow for design structure, especially to allow for correlations among cluster of observations\nUses:\n\n– Cluster randomised trials\n– Cluster random sampling\n– Multistage sampling\n– Health facility cluster survey', 'role': 'assistant'}]