STP Research Methods 2 — Questions and Answers
Question 1: A researcher wants to minimize confounding variables in a clinical study. Which study design is MOST effective for this purpose?
- Cross-sectional survey
- Randomized controlled trial (Correct answer)
- Case-control study
- Cohort study
Correct answer: Randomized controlled trial
Randomized controlled trials use random allocation to distribute confounders equally across groups, making them the gold standard for minimizing confounding.
Question 2: In a research study, internal validity refers to:
- How well results can be generalized to other populations
- Whether the study measures what it claims to measure
- The consistency of measurements over time
- The degree to which findings are free from bias within the study (Correct answer)
Correct answer: The degree to which findings are free from bias within the study
Internal validity refers to the confidence that observed effects are due to the intervention rather than confounding or bias within the study itself.
Question 3: Which sampling method is most appropriate when a researcher needs to ensure representation of several distinct subgroups within a population?
- Simple random sampling
- Convenience sampling
- Stratified random sampling (Correct answer)
- Systematic sampling
Correct answer: Stratified random sampling
Stratified random sampling divides the population into subgroups (strata) and randomly samples from each, ensuring all subgroups are represented.
Question 4: The Hawthorne effect in research describes:
- Participants changing behavior because they know they are being observed (Correct answer)
- Researchers unconsciously influencing outcomes
- Loss of participants during a longitudinal study
- Measurement error introduced by faulty instruments
Correct answer: Participants changing behavior because they know they are being observed
The Hawthorne effect occurs when participants alter their behavior simply because they are aware they are being studied, potentially biasing results.
Question 5: A p-value of 0.03 in a hypothesis test means:
- There is a 3% chance the null hypothesis is true
- There is a 97% chance the alternative hypothesis is true
- The probability of obtaining results this extreme, if H₀ is true, is 3% (Correct answer)
- The effect size is 0.03
Correct answer: The probability of obtaining results this extreme, if H₀ is true, is 3%
A p-value represents the probability of observing results at least as extreme as those obtained, assuming the null hypothesis is true.
Question 6: Which of the following best describes a prospective cohort study?
- Participants are identified after outcomes have already occurred
- Groups with and without a disease are compared for prior exposures
- A defined group is followed forward in time to observe outcomes (Correct answer)
- Participants are randomly assigned to intervention or control groups
Correct answer: A defined group is followed forward in time to observe outcomes
A prospective cohort study enrolls participants based on exposure status and follows them forward in time to observe who develops the outcome of interest.
Question 7: When a measurement tool gives consistent results each time it is used under the same conditions, it demonstrates:
- Validity
- Sensitivity
- Reliability (Correct answer)
- Specificity
Correct answer: Reliability
Reliability refers to the consistency or reproducibility of a measurement, meaning it yields similar results under identical conditions.
STP Research Methods 2
A researcher wants to minimize confounding variables in a clinical study.
Which study design is MOST effective for this purpose?