Psychology Degree Psychological Research Methods 2 — Questions and Answers
Question 1: A researcher measures participants' reaction times before and after a caffeine intervention. What type of design is this?
- Between-subjects design
- Within-subjects design (Correct answer)
- Cross-sectional design
- Case study design
Correct answer: Within-subjects design
A within-subjects design uses the same participants in all conditions, so pre- and post-measures on the same people is within-subjects.
Question 2: Which statistical concept refers to the probability of correctly rejecting a false null hypothesis?
- Alpha level
- Effect size
- Statistical power (Correct answer)
- Confidence interval
Correct answer: Statistical power
Statistical power is the probability of detecting a true effect (rejecting a false null hypothesis), typically targeted at 0.80 or higher.
Question 3: In a factorial design, an interaction effect means that:
- Both independent variables have significant main effects
- The effect of one IV depends on the level of another IV (Correct answer)
- Participants interacted during the study
- The dependent variable affects both independent variables
Correct answer: The effect of one IV depends on the level of another IV
An interaction occurs when the effect of one independent variable differs depending on the level of the other independent variable.
Question 4: What is the primary purpose of counterbalancing in within-subjects designs?
- To increase sample size
- To eliminate demand characteristics
- To control for order and carryover effects (Correct answer)
- To ensure random assignment
Correct answer: To control for order and carryover effects
Counterbalancing varies the order of conditions across participants to prevent order and carryover effects from confounding results.
Question 5: A Likert scale measuring 'strongly disagree' to 'strongly agree' is an example of which measurement level?
- Nominal
- Ratio
- Ordinal (Correct answer)
- Interval
Correct answer: Ordinal
Likert scales are ordinal because responses are ranked, but intervals between points are not guaranteed to be equal.
Question 6: Which type of validity concerns whether a study's findings can be generalized to other populations and settings?
- Internal validity
- Construct validity
- External validity (Correct answer)
- Face validity
Correct answer: External validity
External validity refers to the degree to which study results can be generalized beyond the specific study sample and setting.
Question 7: When a researcher unknowingly treats experimental and control group participants differently, this is called:
- Selection bias
- Experimenter bias (Correct answer)
- Attrition bias
- Placebo effect
Correct answer: Experimenter bias
Experimenter bias occurs when the researcher's expectations inadvertently influence how participants are treated or how data are interpreted.
Psychology Degree Psychological Research Methods 2
A researcher measures participants' reaction times before and after a caffeine intervention.
What type of design is this?