Psychology Degree Psychological Research Methods 3 — Questions and Answers
Question 1: A researcher uses snowball sampling to recruit participants. This method is most appropriate when:
- The population is large and easily accessible
- The target population is hidden or hard to reach (Correct answer)
- Random selection is required
- The study needs a representative national sample
Correct answer: The target population is hidden or hard to reach
Snowball sampling, where participants recruit other participants, is useful for hard-to-reach or stigmatized populations.
Question 2: Which of the following best describes a mediating variable?
- A variable held constant across all conditions
- A third variable that explains the mechanism between X and Y (Correct answer)
- A variable that moderates the strength of a relationship
- An uncontrolled extraneous variable
Correct answer: A third variable that explains the mechanism between X and Y
A mediator explains the process or mechanism by which an independent variable causes a change in the dependent variable.
Question 3: In meta-analysis, what is publication bias?
- The tendency to publish only studies with positive or significant results (Correct answer)
- Bias introduced by the lead author's theoretical orientation
- Errors in how studies are coded for inclusion
- Preferring newer studies over older ones
Correct answer: The tendency to publish only studies with positive or significant results
Publication bias occurs because journals favor statistically significant results, causing the literature to overrepresent positive findings.
Question 4: A Type II error in hypothesis testing occurs when a researcher:
- Rejects a true null hypothesis
- Fails to reject a false null hypothesis (Correct answer)
- Sets alpha too high
- Collects too large a sample
Correct answer: Fails to reject a false null hypothesis
A Type II error (false negative) means failing to detect a real effect — the null hypothesis is false but the researcher does not reject it.
Question 5: Which ethical principle requires that researchers treat all participants fairly and distribute research benefits and burdens equitably?
- Autonomy
- Beneficence
- Justice (Correct answer)
- Nonmaleficence
Correct answer: Justice
The principle of justice requires fair selection of participants and equitable distribution of research risks and benefits across groups.
Question 6: A correlation of r = –0.72 between stress and academic performance indicates:
- Stress causes lower academic performance
- High stress tends to co-occur with lower performance, but causation is not established (Correct answer)
- The relationship explains 72% of variance
- The correlation is statistically non-significant
Correct answer: High stress tends to co-occur with lower performance, but causation is not established
Correlation shows direction and strength of association but does not prove causation; r = –0.72 is a strong negative relationship.
Question 7: An operational definition in research refers to:
- The theoretical concept being studied
- The specific, measurable procedure used to define a variable (Correct answer)
- The statistical test chosen for analysis
- The population from which participants are drawn
Correct answer: The specific, measurable procedure used to define a variable
An operational definition specifies exactly how a variable will be measured or manipulated in a particular study.
Psychology Degree Psychological Research Methods 3
A researcher uses snowball sampling to recruit participants.
This method is most appropriate when: