WACE Psychology Unit 4: Research Methods — Flashcards & Quiz

Q1: Compare independent groups, repeated measures and matched pairs experimental designs.

Independent groups (between-subjects): different participants in each condition. Strength: no order effects. Limitation: individual differences between groups may confound results; requires more participants. Repeated measures (within-subjects): the same participants in all conditions. Strength: controls individual differences. Limitation: order effects (fatigue, practice); addressed by counterbalancing. Matched pairs: participants are matched on key variables and then assigned to different conditions. Strength: reduces individual differences without order effects. Limitation: matching is time-consuming and imperfect; difficult to match on all relevant variables.

Q2: Define independent variable, dependent variable, extraneous variable and confounding variable.

Independent variable (IV): the variable deliberately manipulated by the researcher to observe its effect on the DV. Dependent variable (DV): the variable measured to determine the effect of the IV. Extraneous variable: any variable other than the IV that could potentially affect the DV. If not controlled, it may introduce error but does not systematically vary with the IV. Confounding variable: an extraneous variable that systematically varies with the IV, making it impossible to determine whether the IV or the confound caused changes in the DV. Confounds threaten internal validity.

Q3: Compare random sampling, stratified sampling, convenience sampling and volunteer sampling.

Random sampling: every member of the target population has an equal chance of being selected. High representativeness, minimises sampling bias. Difficult and time-consuming to achieve. Stratified sampling: the population is divided into subgroups (strata) and participants are randomly selected from each stratum in proportion to their representation. Ensures key subgroups are represented. Convenience sampling: selecting participants who are readily available (e.g. university students). Quick and easy but low representativeness. Volunteer (self-selected) sampling: participants choose to participate (e.g. responding to an advertisement). May introduce volunteer bias — volunteers may differ systematically from non-volunteers.

Q4: What are the key ethical principles for psychological research?

Key ethical principles (NHMRC guidelines): Informed consent — participants must be told the purpose, procedures, risks and their right to withdraw before agreeing to participate. Voluntary participation and right to withdraw — participants must not be coerced and can leave at any time without penalty. Confidentiality and anonymity — personal data must be protected and reported anonymously. Deception — only permitted when essential, when no alternative method exists and when participants are debriefed afterward. Debriefing — informing participants of the true purpose and any deception after the study. Do no harm (beneficence/non-maleficence) — the benefits of the research must outweigh any potential risks to participants.

Q5: Distinguish between reliability and validity in psychological research.

Reliability: the consistency of a measure. A reliable measure produces similar results under consistent conditions. Types: test-retest reliability (same results when repeated), inter-rater reliability (different observers agree), internal consistency (items within a test measure the same construct). Validity: the extent to which a measure actually measures what it claims to measure. Types: internal validity (the IV caused changes in the DV, not confounds), external validity (results can be generalised beyond the study — ecological validity and population validity), construct validity (the measure accurately captures the intended psychological construct), face validity (the measure appears to measure what it claims).

Q6: Compare experiments, observations, surveys and case studies.

Experiments: manipulate IV, measure DV, control extraneous variables. Strengths: can establish cause-and-effect, high internal validity. Limitations: artificial settings may reduce ecological validity. Observations: systematically record naturally occurring behaviour. Strengths: high ecological validity, no demand characteristics. Limitations: cannot establish causation, observer bias possible. Surveys: collect self-reported data via questionnaires or interviews. Strengths: efficient for large samples, collect subjective experiences. Limitations: social desirability bias, question wording effects. Case studies: in-depth investigation of a single individual or small group. Strengths: rich, detailed data, useful for rare conditions. Limitations: cannot generalise, researcher bias, no cause-and-effect.

Q7: Describe the measures of central tendency and their appropriate use.

Mean: the arithmetic average (sum of all values ÷ number of values). Most commonly used. Sensitive to outliers. Best for: interval/ratio data with a normal distribution. Median: the middle value when data is ordered. Not affected by outliers. Best for: ordinal data or skewed distributions. Mode: the most frequently occurring value. Can be used with nominal data. Useful for identifying the most common response. There can be no mode, one mode or multiple modes. Choosing the appropriate measure depends on the data type and distribution.

Q8: What are measures of dispersion and why are they important?

Measures of dispersion describe the spread of data around the central tendency: Range: the difference between the highest and lowest values. Simple to calculate but affected by outliers. Standard deviation: measures the average distance of each data point from the mean. A small SD indicates data points are clustered close to the mean; a large SD indicates greater spread. Not affected by outliers as severely as the range. Standard deviation is the most informative measure of dispersion because it uses all data points and relates directly to the normal distribution (68% of data falls within ±1 SD of the mean).

Q1: In a repeated measures design, different participants are used in each experimental condition.

Answer: FALSE

In a repeated measures (within-subjects) design, the same participants are used in all conditions. Different participants in each condition describes an independent groups (between-subjects) design.

Q2: A confounding variable is an extraneous variable that systematically varies with the independent variable.

Answer: TRUE

A confounding variable is a specific type of extraneous variable that changes systematically along with the IV, making it impossible to determine whether the IV or the confound caused the observed changes in the DV. Confounds are the most serious threat to internal validity.

Q3: Convenience sampling ensures that every member of the target population has an equal chance of being selected.

Answer: FALSE

Random sampling ensures equal selection probability for all population members. Convenience sampling selects readily available participants (e.g. nearby students), which does not give all population members an equal chance and may result in a biased, unrepresentative sample.

Q4: Debriefing involves informing participants of the true purpose and any deception after the study is completed.

Answer: TRUE

Debriefing is an ethical requirement where participants are informed of the study’s true purpose, any deception used, and the reasons for it after the study is completed. It also provides an opportunity to address any distress and allows participants to withdraw their data if they wish.

Q5: A measure can be valid without being reliable.

Answer: FALSE

A valid measure must also be reliable. If a measure gives inconsistent (unreliable) results, it cannot accurately measure what it claims to. However, a measure can be reliable (consistent) without being valid (accurate) — it may consistently measure the wrong thing.

Experimental Design and Variables

Understanding the three main experimental designs (independent groups, repeated measures, matched pairs) and the types of variables (IV, DV, extraneous, confounding) is fundamental. SCSA exams require you to identify designs in described studies, recommend appropriate designs for research questions and explain how to control extraneous variables.

Sampling and Ethics

Knowing the strengths and limitations of different sampling methods and the key ethical principles (informed consent, right to withdraw, confidentiality, debriefing) is essential. SCSA frequently presents a study and asks you to evaluate its sampling strategy and identify ethical concerns.

Reliability and Validity

Distinguishing between reliability (consistency) and validity (accuracy), and understanding their subtypes (internal, external, construct validity; test-retest, inter-rater reliability), is a core exam skill. SCSA expects you to evaluate the reliability and validity of described research and suggest improvements.

Data Analysis and Interpretation

Being able to calculate and interpret measures of central tendency (mean, median, mode) and dispersion (range, standard deviation), and understanding the difference between correlation and causation, is essential for the data analysis component of the SCSA exam.

What does WACE Psychology Unit 4 cover about research methods?

Unit 4 covers types of research (experiments, observations, surveys, case studies), experimental design (independent groups, repeated measures, matched pairs), variables (IV, DV, extraneous, confounding), sampling methods, ethical principles, reliability and validity, and data analysis including measures of central tendency and dispersion.

Are these flashcards aligned to the SCSA curriculum?

Yes — every flashcard and quiz question is mapped to the SCSA WACE Psychology Units 3–4 syllabus for the research methods content area.

How important are research methods for the WACE Psychology exam?

Research methods are assessed throughout the WACE Psychology exam, not just in dedicated questions. Understanding experimental design, variables, ethics and validity allows you to evaluate the research evidence cited in any topic, which is essential for extended response questions.