A Level Sociology OCR Practice Exam

Systematic sampling involves what selection method?

1. Irregular selection of participants

2. Selection of every nth unit from the population

3. Selection based on researcher's discretion

4. Random selection without replacement

The correct answer is: Selection of every nth unit from the population

Systematic sampling is characterized by selecting participants at regular intervals from a larger population. The method involves determining a sampling interval (often denoted as "n") based on the desired sample size and the total population size. Once the interval is established, every nth unit is chosen until the required sample size is reached. This structured approach ensures that the selection process is consistent and can help mitigate potential bias that might arise with more arbitrary methods. In contrast, the other options describe different sampling methods or strategies that do not align with the principles of systematic sampling. Irregular selection would imply a lack of consistency, which contradicts the systematic approach. Selection based on the researcher’s discretion introduces potential bias and subjectivity, making it less systematic. Random selection without replacement does not emphasize the consistent interval aspect of systematic sampling, as it typically involves selecting units randomly from a population without the interval structure. Thus, the correct answer reflects the foundational concept of systematic sampling.