Research methods + experimental designs

Question 1

Types of Experiments

Answer 1

1. Laboratory Experiment
   o Conducted in a controlled environment.
   o Strength: High control over variables allows for replication and establishing cause-effect relationships.
   o Limitation: Low ecological validity; artificial setting may result in unnatural behaviour.
2. Field Experiment
   o Conducted in a natural environment, but the researcher manipulates the independent variable (IV).
   o Strength: Higher ecological validity than lab experiments.
   o Limitation: Less control over extraneous variables.
3. Natural Experiment
   o The IV is not manipulated by the researcher; it occurs naturally.
   o Strength: Useful when ethical or practical reasons prevent manipulation.
   o Limitation: Lack of control over the IV and extraneous variables, making causal conclusions difficult.
4. Quasi-Experiment
   o The IV is based on an existing difference between people (e.g., age, gender).
   o Strength: Useful for studying naturally occurring differences.
   o Limitation: No random assignment to conditions, limiting control.

Question 2

Experimental Designs

Answer 2

1. Independent Groups Design
   o Different participants are used in each condition of the experiment.
   o Strength: No order effects, as participants only take part in one condition.
   o Limitation: Participant variables may affect results (differences between participants in each group).
   o Control: Random allocation to conditions.
2. Repeated Measures Design
   o The same participants take part in all conditions of the experiment.
   o Strength: Controls for participant variables since the same people are used.
   o Limitation: Risk of order effects (e.g., fatigue or practice).
   o Control: Counterbalancing can be used to minimise order effects.
3. Matched Pairs Design
   o Pairs of participants are matched on relevant variables, and one from each pair is allocated to each condition.
   o Strength: Reduces participant variables while avoiding order effects.
   o Limitation: Time-consuming to match participants and may not control all participant differences.

Question 3

Types of Variables

Answer 3

1. Independent Variable (IV)
   o The variable manipulated by the researcher to observe its effect.
2. Dependent Variable (DV)
   o The variable that is measured to see the effect of the IV.
3. Extraneous Variables (EVs)
   o Other variables that could influence the DV. Should be controlled to avoid confounding the results.
4. Confounding Variables
   o Variables that have unintentionally affected the DV and varied systematically with the IV.
   o Impact: They can obscure the true relationship between the IV and DV.

Question 4

Control of Variables

Answer 4

1. Randomisation
   o The use of chance to control the effects of bias when designing materials or deciding the order of conditions.
2. Counterbalancing
   o Used in repeated measures to control order effects.
   o Types:
    ABBA design: Participants do condition A followed by B, then condition B followed by A.
3. Standardisation
   o Ensuring all participants are subject to the same environment, information, and experience.
   o Impact: Increases the reliability of the study.
4. Single-Blind Procedure
   o Participants are unaware of the condition they are in to reduce demand characteristics.
5. Double-Blind Procedure
   o Both the participants and the researcher are unaware of the condition to prevent researcher bias.

Question 5

Hypotheses

Answer 5

1. Directional (One-tailed) Hypothesis
   o States the direction of the expected difference or relationship between variables (e.g., “Participants will recall more words in a quiet environment than in a noisy environment”).
2. Non-Directional (Two-tailed) Hypothesis
   o States that there will be a difference or relationship between variables but does not predict the direction (e.g., “There will be a difference in word recall between noisy and quiet environments”).
3. Null Hypothesis
   o States that any difference or relationship is due to chance (e.g., “There will be no significant difference in word recall between noisy and quiet environments”).

Question 6

Ethical Considerations

Answer 6

1. Informed Consent
   o Participants must be fully informed about the nature of the study and provide voluntary consent.
2. Deception
   o Must be avoided unless necessary for the study. If used, participants must be debriefed afterward.
3. Right to Withdraw
   o Participants can leave the study at any time without penalty.
4. Confidentiality
   o Personal information must remain private and not be disclosed.
5. Protection from Harm
   Participants should not be exposed to risks greater than those they would encounter in daily life.

Question 7

Reliability and Validity

Answer 7

1. Internal Reliability
   o Consistency within a test or measurement (e.g., if the test is split in half, both halves should produce similar results).
2. External Reliability
   o The consistency of results across time and different contexts (e.g., test-retest reliability).
3. Internal Validity
   o The extent to which the study measures what it intends to measure and the elimination of confounding variables.
4. External Validity
   o The extent to which the results can be generalised to other settings (ecological validity), populations (population validity), and times (temporal validity).

Question 8

Sampling Methods

Answer 8

1. Random Sampling
   o Every member of the population has an equal chance of being selected.
   o Strength: Minimises bias, increasing generalisability.
   o Limitation: Difficult to achieve in large populations.
2. Opportunity Sampling
   o Participants are selected based on availability.
   o Strength: Quick and easy.
   o Limitation: High risk of bias, reducing generalisability.
3. Systematic Sampling
   o Every nth person in a target population is selected.
   o Strength: Avoids researcher bias.
   o Limitation: Can still be unrepresentative.
4. Stratified Sampling
   o Divides the population into strata and selects participants from each group proportionally.
   o Strength: Produces a representative sample.
   o Limitation: Time-consuming.

Question 9

Data Analysis

Answer 9

1. Quantitative Data
   o Numerical data that can be statistically analysed (e.g., mean, median, mode).
   o Strength: Can be easily compared and analysed.
   o Limitation: May oversimplify complex behaviour.
2. Qualitative Data
   o Descriptive data providing insights into thoughts, feelings, or opinions.
   o Strength: Provides rich, detailed information.
   o Limitation: Difficult to analyse and compare.
3. Measures of Central Tendency
   o Mean: Average score.
   o Median: Middle score in a data set.
   o Mode: Most frequent score.
4. Measures of Dispersion
   o Range: Difference between the highest and lowest scores.
   o Standard Deviation: Measure of the spread of scores around the mean.