Which type of poll uses a limited number of respondents drawn so that every person in the population has an equal chance of being selected?

• A. Random sample
• B. Stratified sample
• C. Convenience sample
• D. Systematic sample

Answer: (A)

Simple random sampling is the approach where every person has an equal chance of being selected, which is exactly what this question describes. With a limited number of respondents, you ensure fairness by using a random method—like assigning numbers to everyone and using a random generator to pick which numbers are included. In this way, each individual’s probability of being chosen is the same, regardless of any characteristic, so the sample is most likely to mirror the population as a whole (assuming the sampling frame is complete). For example, if there are 10,000 people and you want 500, you’d randomly select 500 distinct people; each person has a 1-in-20 chance.

Stratified sampling divides the population into subgroups and samples within each—this helps ensure representation of subgroups but doesn't give every person equal odds, since some groups may be sampled more or less heavily. Convenience sampling picks the easiest respondents, which introduces bias. Systematic sampling uses every kth person after a random start; it can approximate equal chances if done carefully, but it isn’t guaranteed to give each person an identical probability.