Explain why a researcher would use stratified sampling.

• A. To oversample the largest subgroup
• B. To ensure important subgroups are adequately represented in the sample
• C. To simplify data collection
• D. To eliminate the need for a sampling frame

Answer: (B)

Stratified sampling splits the population into subgroups that are relevant to the study and then samples from each subgroup. The goal is to ensure that important subgroups are adequately represented in the final sample, so that estimates for those groups are reliable and comparisons across groups are valid. This approach reduces sampling error for subgroup analyses and prevents small but important groups from being underrepresented. It isn’t about oversampling the largest subgroup, and it doesn’t necessarily simplify data collection; it still requires a sampling frame to identify members of each subgroup.