Psychology Degree Research Methods and Ethics 4 — Questions and Answers
Question 1: Which of the following is the best example of a confounding variable?
- The dependent variable measured at posttest
- A variable that varies systematically with the IV and also affects the DV (Correct answer)
- Random error in measurement instruments
- A mediating variable in a causal chain
Correct answer: A variable that varies systematically with the IV and also affects the DV
A confound co-varies with the independent variable and independently influences the dependent variable, threatening internal validity.
Question 2: Content validity of a test is best evaluated by:
- Correlating scores with a criterion measured concurrently
- Having subject matter experts judge whether items represent the domain (Correct answer)
- Examining the factor structure via factor analysis
- Computing Cronbach's alpha
Correct answer: Having subject matter experts judge whether items represent the domain
Content validity is established through expert review to ensure the test items adequately sample the relevant content domain.
Question 3: What does it mean if a study has low statistical power?
- It is likely to produce false positives
- It has a high probability of failing to detect a true effect (Correct answer)
- The sample is not representative
- The measures are unreliable
Correct answer: It has a high probability of failing to detect a true effect
Low power means a high probability of a Type II error — failing to reject a false null hypothesis when a true effect exists.
Question 4: An IRB review is most concerned with which three core ethical principles from the Belmont Report?
- Validity, reliability, and generalizability
- Respect for persons, beneficence, and justice (Correct answer)
- Consent, debriefing, and confidentiality
- Randomization, control, and replication
Correct answer: Respect for persons, beneficence, and justice
The Belmont Report establishes respect for persons (autonomy/consent), beneficence (maximize benefit/minimize harm), and justice (fair distribution) as foundational principles.
Question 5: A researcher studying suicidal ideation in teenagers omits the topic from the informed consent form to avoid distressing participants before the study. This is:
- Acceptable because it protects participants
- A violation of informed consent requirements (Correct answer)
- Permitted as a form of passive deception
- Required under HIPAA privacy rules
Correct answer: A violation of informed consent requirements
Participants must be told the general nature of a study; omitting a central sensitive topic violates their right to make an informed decision about participation.
Question 6: What is the defining feature of a quasi-experimental design?
- It uses no control group
- It lacks random assignment to conditions (Correct answer)
- It relies solely on self-report measures
- It is conducted outside of laboratory settings
Correct answer: It lacks random assignment to conditions
Quasi-experiments manipulate an independent variable but without random assignment, limiting causal conclusions compared to true experiments.
Question 7: Which statistic is used to estimate the proportion of variance in the dependent variable explained by the independent variable?
- Cohen's d
- Pearson's r
- Eta-squared (η²) (Correct answer)
- Standard error of the mean
Correct answer: Eta-squared (η²)
Eta-squared (η²) is a variance-accounted-for effect size statistic commonly reported with ANOVA results.
Psychology Degree Research Methods and Ethics 4
Which of the following is the best example of a confounding variable?