Questions: Identify the sampling method (simple random sampling, systematic sampling, convenience sampling, cluster sampling, or stratified sampling) in the following study. Researchers studying the use of laxatives select 42 participants between the ages of 20 and 29, 42 participants between the ages of 30 and 39, and 42 participants between the ages of 40 and 49. What type of sampling is used? - Simple random sampling - Systematic sampling - Stratified sampling - Cluster sampling - Convenience sampling

The answer is Stratified sampling: Researchers studying the use of laxatives select 42 participants between the ages of 20 and 29, 42 participants between the ages of 30 and 39, and 42 participants between the ages of 40 and 49.

Explanation for each option:

1. Simple random sampling: This method involves selecting participants randomly from the entire population, where each individual has an equal chance of being chosen. In this study, participants are selected based on age groups, not randomly from the entire population, so this is not the correct method.

2. Systematic sampling: This involves selecting every nth individual from a list or sequence. The study does not mention any systematic selection process, so this is not the correct method.

3. Stratified sampling: This method involves dividing the population into distinct subgroups or strata (in this case, age groups) and then randomly selecting participants from each stratum. The study clearly divides participants into age groups and selects an equal number from each, which is characteristic of stratified sampling.

4. Cluster sampling: This involves dividing the population into clusters, usually based on geographical areas or other natural groupings, and then randomly selecting entire clusters. The study does not involve selecting entire clusters, so this is not the correct method.

5. Convenience sampling: This involves selecting participants who are easiest to reach or contact. The study specifies age groups and equal numbers from each, indicating a more structured approach than convenience sampling.

Therefore, the sampling method used in this study is stratified sampling.