&;Design Effect&; is assiciated with which of the following sampling techniques-
**Core Concept**
The design effect is a measure of the degree to which a survey or study's sampling design affects the variability of estimates. It is particularly relevant in cluster sampling, where groups or clusters are sampled instead of individual units.
**Why the Correct Answer is Right**
The design effect is most closely associated with cluster sampling, as it takes into account the correlation within clusters and the potential for over-dispersion. This is because cluster sampling can lead to a higher degree of variability in estimates due to the non-independent sampling of units within clusters. The design effect adjusts for this by providing a multiplier that reflects the increased variability.
**Why Each Wrong Option is Incorrect**
**Option A:** Not directly related to the design effect, as it is more commonly associated with stratified sampling.
**Option B:** While stratified sampling can also lead to design effects, it is not the most closely associated with this concept.
**Option C:** Not relevant to the design effect, as it is more commonly associated with random sampling.
**Clinical Pearl / High-Yield Fact**
A key aspect of cluster sampling is that it can lead to a higher design effect, which can result in wider confidence intervals and reduced precision of estimates.
**Correct Answer: C. Cluster sampling.**