All of the following are true about cluster sampling except –
**Core Concept**
Cluster sampling is a type of probability sampling method where the population is divided into clusters or groups, and a random sample of these clusters is selected for the study. This method is often used in public health and medical research to study disease prevalence or outcomes in specific geographic areas.
**Why the Correct Answer is Right**
Cluster sampling involves selecting a random sample of clusters from the population, and then studying all individuals within those selected clusters. This method can be more efficient and cost-effective than individual random sampling, especially when the population is large and dispersed. However, it may also lead to biased results if the selected clusters are not representative of the overall population.
**Why Each Wrong Option is Incorrect**
**Option A:** Cluster sampling can be more efficient and cost-effective than individual random sampling. **(Correct, this is a true statement about cluster sampling)**
**Option B:** Cluster sampling is not suitable for studying rare diseases. **(Incorrect, cluster sampling can be used to study rare diseases by selecting clusters with high prevalence rates)**
**Option C:** Cluster sampling involves selecting a random sample of individuals from the population. **(Incorrect, cluster sampling involves selecting a random sample of clusters, not individuals)**
**Option D:** Cluster sampling is a type of non-probability sampling method. **(Incorrect, cluster sampling is a type of probability sampling method)**
**Clinical Pearl / High-Yield Fact**
When using cluster sampling, it's essential to ensure that the selected clusters are representative of the overall population to avoid biased results.
**Correct Answer: C. Cluster sampling involves selecting a random sample of individuals from the population.**