Which sampling method selects every kth member of the population, with k approximately N/n?

Which sampling method selects every kth member of the population, with k approximately N/n?

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

Answer: (A)

Systematic sampling uses a fixed interval to select members from an ordered list. To get about n selections from a population of size N, you pick a skip interval k roughly equal to N divided by n and then choose every kth item after starting at a random position within the first k items. This approach yields about N/k samples, which is about n when k ≈ N/n. Starting at a random point helps prevent bias if the list has any ordering that could influence which items get chosen. The method is simple and ensures the sample is spread across the population rather than clustered, though it can be biased if the population has a repeating pattern that aligns with the chosen interval.

Systematic sampling uses a fixed interval to select members from an ordered list. To get about n selections from a population of size N, you pick a skip interval k roughly equal to N divided by n and then choose every kth item after starting at a random position within the first k items. This approach yields about N/k samples, which is about n when k ≈ N/n. Starting at a random point helps prevent bias if the list has any ordering that could influence which items get chosen. The method is simple and ensures the sample is spread across the population rather than clustered, though it can be biased if the population has a repeating pattern that aligns with the chosen interval.