AP Stats Sampling Methods and Design 1 — Questions and Answers
Question 1: What is the purpose of random sampling?
- To ensure every member of the population has an equal chance of being selected (Correct answer)
- To select only convenient participants
- To guarantee a specific sample size
- To eliminate all sampling error
Correct answer: To ensure every member of the population has an equal chance of being selected
Random sampling gives each population member an equal selection probability, reducing selection bias and supporting generalizability.
Question 2: What is stratified sampling?
- Dividing the population into subgroups and sampling from each proportionally (Correct answer)
- Randomly selecting from the entire population without divisions
- Sampling every nth individual from a list
- Selecting the most convenient participants
Correct answer: Dividing the population into subgroups and sampling from each proportionally
Stratified sampling ensures representation of important subgroups by dividing the population into strata and sampling from each.
Question 3: What is sampling bias?
- A systematic error that results in a non-representative sample (Correct answer)
- Any error that occurs during data collection
- The natural variation in sample statistics
- A preference for larger sample sizes
Correct answer: A systematic error that results in a non-representative sample
Sampling bias occurs when the selection method systematically favors certain members over others, producing unrepresentative results.
Question 4: What determines the minimum sample size needed for a study?
- Desired confidence level, margin of error, and population variability (Correct answer)
- The researchers preference
- The total population size only
- The number of variables in the study only
Correct answer: Desired confidence level, margin of error, and population variability
Sample size calculations consider the desired precision, confidence level, population variability, and effect size.
Question 5: What is cluster sampling?
- Dividing the population into clusters, then randomly selecting entire clusters to study (Correct answer)
- Selecting individuals who are clustered together by age
- Sampling the same individuals multiple times
- Choosing the largest groups for the sample
Correct answer: Dividing the population into clusters, then randomly selecting entire clusters to study
Cluster sampling randomly selects groups (clusters) rather than individuals, then studies all members within selected clusters.
Question 6: Why is non-response bias a concern in survey research?
- Non-respondents may differ systematically from respondents, skewing results (Correct answer)
- It only affects very small samples
- Non-response has no impact on results
- It is only a concern for telephone surveys
Correct answer: Non-respondents may differ systematically from respondents, skewing results
Non-response bias occurs when people who do not respond differ from those who do, potentially distorting findings.
AP Stats Sampling Methods and Design 1
What is the purpose of random sampling?