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
For which of the following sampling, a Design effect is used? 
Select and explain. 
A. Simple random sampling, B. Systematic random sampling, C. Cluster random sampling, D. Stratified random sampling
C: Cluster random sampling
Answer: C: Cluster random sampling 
Explanation: DESIGN EFFECT

Definition: Adjustment used in few study/sampling designs to allow for design structure, especially to allow for correlations among cluster of observations
Uses:

– Cluster randomised trials
– Cluster random sampling
– Multistage sampling
– Health facility cluster survey