Problem
Identify the sampling method (simple random sampling, systematic sampling, convenience sampling, cluster samplin or stratified sampling) in the following study. Researchers studying the use of antidepressants select 63 participants between the ages of 20 and 29,63 participant between the ages of 30 and 39 , and 63 participants between the ages of 40 and 49 . What type of sampling is used? Systematic sampling Stratified sampling Simple random sampling Convenience sampling Cluster sampling
Solution
Step 1 ：The researchers are dividing the population into different age groups (strata) and then selecting participants from each group. This is a characteristic of stratified sampling.
Step 2 ：Final Answer: \(\boxed{\text{Stratified sampling}}\)
