PRC Sampling Techniques & Participant Recruitment 2 — Questions and Answers
Question 1: A researcher wants to ensure that rural, suburban, and urban populations are proportionally represented in a national survey. Which sampling method is most appropriate?
- Simple random sampling
- Stratified random sampling (Correct answer)
- Snowball sampling
- Convenience sampling
Correct answer: Stratified random sampling
Stratified random sampling divides the population into subgroups (strata) and samples proportionally from each, ensuring representation of all geographic categories.
Question 2: In cluster sampling, what is the primary unit of random selection?
- Individual respondents
- Naturally occurring groups (Correct answer)
- Survey questions
- Data collection intervals
Correct answer: Naturally occurring groups
Cluster sampling randomly selects naturally occurring groups (clusters) such as schools or neighborhoods, then surveys all or a sample of members within selected clusters.
Question 3: Which condition makes snowball sampling particularly useful?
- The population is large and clearly defined
- The population is hard to reach or identify (Correct answer)
- Budget constraints require minimal travel
- Online recruitment is prohibited
Correct answer: The population is hard to reach or identify
Snowball sampling is ideal when the target population is hidden or difficult to identify, such as undocumented immigrants or illicit drug users, where participants refer others.
Question 4: A sampling frame that excludes certain segments of the target population will most likely result in:
- Increased statistical power
- Coverage error (Correct answer)
- Reduced response burden
- Higher cooperation rates
Correct answer: Coverage error
Coverage error occurs when the sampling frame does not include all members of the target population, causing systematic exclusion and potential bias.
Question 5: What distinguishes purposive sampling from probability sampling?
- Purposive sampling uses random number generators
- Purposive sampling relies on researcher judgment to select participants (Correct answer)
- Purposive sampling requires a complete sampling frame
- Purposive sampling yields statistically generalizable results
Correct answer: Purposive sampling relies on researcher judgment to select participants
Purposive sampling involves deliberate selection of participants based on specific characteristics deemed relevant to the research, rather than random selection.
Question 6: A researcher mails surveys to every 10th name on a voter registration list. This is an example of:
- Stratified sampling
- Cluster sampling
- Systematic sampling (Correct answer)
- Quota sampling
Correct answer: Systematic sampling
Systematic sampling selects every nth element from a list after a random starting point, making it efficient when a complete ordered list is available.
Question 7: Which type of error is introduced when participants who respond to a survey differ systematically from those who do not respond?
- Sampling error
- Nonresponse bias (Correct answer)
- Measurement error
- Coverage error
Correct answer: Nonresponse bias
Nonresponse bias occurs when respondents and non-respondents differ on key variables, making survey results unrepresentative of the full target population.
PRC Sampling Techniques & Participant Recruitment 2
A researcher wants to ensure that rural, suburban, and urban populations are proportionally represented in a national survey.
Which sampling method is most appropriate?