Which sampling method divides the population into mutually exclusive groups called strata and randomly samples from each group?

Which sampling method divides the population into mutually exclusive groups called strata and randomly samples from each group?

• A. Stratified sampling
• B. Cluster sampling
• C. Systematic sampling
• D. Simple random sampling

Answer: (A)

Grouping the population into distinct subgroups that cover everyone and then sampling from each subgroup ensures representation of those subgroups in the final sample. This approach, called stratified sampling, divides the population into mutually exclusive strata and then randomly samples within each one. It helps the sample reflect the population’s structure and can reduce variability within subgroups, leading to more precise estimates overall. The description fits stratified sampling because the method relies on creating strata that are disjoint and collectively cover the entire population, followed by random selection from every stratum. In contrast, cluster sampling first groups into clusters and then samples whole clusters; systematic sampling selects every k-th person on a list; simple random sampling draws individuals from the entire population without organizing by subgroups.

Grouping the population into distinct subgroups that cover everyone and then sampling from each subgroup ensures representation of those subgroups in the final sample. This approach, called stratified sampling, divides the population into mutually exclusive strata and then randomly samples within each one. It helps the sample reflect the population’s structure and can reduce variability within subgroups, leading to more precise estimates overall.

The description fits stratified sampling because the method relies on creating strata that are disjoint and collectively cover the entire population, followed by random selection from every stratum. In contrast, cluster sampling first groups into clusters and then samples whole clusters; systematic sampling selects every k-th person on a list; simple random sampling draws individuals from the entire population without organizing by subgroups.