A-Level Psychology Research Methods — Questions and Answers
Question 1: What is the key feature that distinguishes an experiment from a correlational study?
- Manipulation of an independent variable to observe its effect on a dependent variable (Correct answer)
- The use of a large sample size
- Data being collected through questionnaires
- The study taking place in a natural setting
Correct answer: Manipulation of an independent variable to observe its effect on a dependent variable
The defining feature of an experiment is the deliberate manipulation of an independent variable (IV) while measuring its effect on a dependent variable (DV), with control of extraneous variables. Correlational studies only measure the relationship between co-variables without manipulation.
Question 2: A researcher finds a correlation coefficient of r = -0.85. What does this indicate?
- A strong negative correlation (Correct answer)
- A weak negative correlation
- A strong positive correlation
- No correlation
Correct answer: A strong negative correlation
The correlation coefficient ranges from -1 to +1. A value of -0.85 indicates a strong negative correlation — as one variable increases, the other tends to decrease. The closer to -1, the stronger the negative relationship.
Question 3: What is a demand characteristic in psychological research?
- A cue in the study that leads participants to guess the aim and alter their behaviour accordingly (Correct answer)
- The minimum number of participants required for statistical significance
- A characteristic that the researcher demands participants must have
- The ethical requirement to obtain informed consent
Correct answer: A cue in the study that leads participants to guess the aim and alter their behaviour accordingly
Demand characteristics are cues in the experimental situation that convey the hypothesis to participants, potentially leading them to change their behaviour (e.g., through the 'please-u' effect or screw-you effect). This threatens internal validity.
Question 4: Which experimental design involves each participant experiencing all conditions of the independent variable?
- Repeated measures design (Correct answer)
- Independent groups design
- Matched pairs design
- Cross-sectional design
Correct answer: Repeated measures design
In a repeated measures design, the same participants take part in every condition. This controls for individual differences but introduces order effects (fatigue, practice), which can be managed through counterbalancing.
Question 5: What is the purpose of random allocation in an independent groups design?
- To reduce the effect of participant variables (confounding variables) across conditions (Correct answer)
- To ensure every member of the target population has an equal chance of being selected
- To prevent order effects between conditions
- To increase the ecological validity of the study
Correct answer: To reduce the effect of participant variables (confounding variables) across conditions
Random allocation assigns participants to conditions by chance (e.g., coin flip), distributing participant variables evenly across groups. This reduces systematic bias and increases confidence that differences in the DV are caused by the IV, not pre-existing differences.
Question 6: A Type I error in hypothesis testing occurs when:
- The null hypothesis is rejected when it is actually true (a false positive) (Correct answer)
- The null hypothesis is accepted when it is actually false (a false negative)
- The sample size is too small to detect an effect
- The wrong statistical test is used
Correct answer: The null hypothesis is rejected when it is actually true (a false positive)
A Type I error (false positive) means concluding there is a significant effect when there isn't one. The probability of a Type I error equals the significance level (alpha), typically set at 0.05 (5%). It is the 'optimistic' error.
A-Level Psychology Research Methods
What is the key feature that distinguishes an experiment from a correlational study?