Which sampling method selects items at a fixed interval from a list after a random start?

Which sampling method selects items at a fixed interval from a list after a random start?

• A. Systematic Random Sample
• B. Stratified Sampling
• C. Cluster Samples
• D. Quota Sampling

Answer: (A)

Systematic sampling uses a fixed interval to select items from a list after choosing a random starting point. You determine the interval by dividing the list size by the desired sample size. After picking a random start within the first interval, you continue by taking every kth item. This approach spreads the sample across the list and is straightforward, but it relies on there being no hidden pattern in the list that matches the interval. For example, with 1,000 items and a plan for 100, the interval is 10. You would pick a random starting position between 1 and 10 (say 4), then select the 4th, 14th, 24th items, and so on. This differs from stratified sampling (sampling within predefined subgroups), cluster sampling (sampling entire clusters or using clusters), and quota sampling (a non-probability method that fills predefined quotas).

Systematic sampling uses a fixed interval to select items from a list after choosing a random starting point. You determine the interval by dividing the list size by the desired sample size. After picking a random start within the first interval, you continue by taking every kth item. This approach spreads the sample across the list and is straightforward, but it relies on there being no hidden pattern in the list that matches the interval.

For example, with 1,000 items and a plan for 100, the interval is 10. You would pick a random starting position between 1 and 10 (say 4), then select the 4th, 14th, 24th items, and so on.

This differs from stratified sampling (sampling within predefined subgroups), cluster sampling (sampling entire clusters or using clusters), and quota sampling (a non-probability method that fills predefined quotas).