Which sampling method obtains a sample by selecting every 5th or 7th person?

Which sampling method obtains a sample by selecting every 5th or 7th person?

• A. Systematic Sampling
• B. Random Sampling
• C. Stratified Sampling
• D. Opportunity Sampling

Answer: (A)

Systematic sampling uses a fixed interval to select participants from a list. You start at a random position and then pick every nth person—like every fifth or every seventh. This approach is efficient and easy to implement, and it helps spread the sample across the population rather than clustering around a particular section. It reduces selection bias compared with ad-hoc choices, while still being straightforward to carry out. A caveat is that if the population list has a hidden pattern that aligns with the interval, the sample can become biased. This method differs from random sampling, where each person has an equal chance of being chosen; from stratified sampling, which divides the population into subgroups and samples from each; and from opportunity sampling, which relies on who is readily available. So selecting every 5th or 7th person is the hallmark of systematic sampling.

Systematic sampling uses a fixed interval to select participants from a list. You start at a random position and then pick every nth person—like every fifth or every seventh. This approach is efficient and easy to implement, and it helps spread the sample across the population rather than clustering around a particular section. It reduces selection bias compared with ad-hoc choices, while still being straightforward to carry out. A caveat is that if the population list has a hidden pattern that aligns with the interval, the sample can become biased. This method differs from random sampling, where each person has an equal chance of being chosen; from stratified sampling, which divides the population into subgroups and samples from each; and from opportunity sampling, which relies on who is readily available. So selecting every 5th or 7th person is the hallmark of systematic sampling.