Variables & Constructs
What is the difference between an Independent Variable (IV) and a Dependent Variable (DV)?
The IV is the variable manipulated by the experimenter; the DV is the variable that changes as a result of that manipulation.
What is the main goal of "Random Sampling" in quantitative research?
To give every member of the target population an equal chance of being selected, increasing representativeness.
In which design is the IV manipulated by randomly allocating participants into different groups?
Independent Measures Design.
What is "Internal Validity" and what does it measure in an experiment?
It relates to the methodological quality and credibility; it measures if the IV actually caused the change in the DV.
What is "Experimenter Bias" and how can it be avoided?
When a researcher unintentionally influences results; avoided using a double-blind design.
Explain the process of "Operationalization" using "Anxiety" as an example.
Operationalization is expressing a construct in observable terms. E.g., Anxiety can be measured by cortisol levels or a self-report score.
Define "Representative Sample" and why it matters for generalization.
A sample that reflects all essential characteristics of the target population; it allows findings to be generalized.
What is a "Repeated Measures" design and why is it also called "within-subject"?
The same group of participants is exposed to all conditions; they are compared against their own performance.
Describe the difference between "Ecological Validity" and "Population Validity."
Ecological: Generalizability to other settings. Population: Generalizability to other people/target population.
Explain "Demand Characteristics" and why they are common in repeated measures.
When participants guess the aim and change their behavior; common in repeated measures because they see multiple conditions.
What are "Confounding Variables" and why must they be controlled?
They are outside variables that can interfere with the IV-DV relationship; they must be kept constant to ensure the IV caused the change.
How does "Stratified Sampling" ensure a sample is representative?
It involves recruiting participants randomly while maintaining the same proportions of key characteristics (e.g., age) found in the population.
What are "Order Effects" and in which specific design do they occur?
Fatigue or practice effects that happen when a participant does a second trial; occurs in Repeated Measures.
What is "Construct Validity" and how does it relate to operationalization?
It measures the quality of operationalizations; it's high if the leap from observable behavior to theory is justified.
What is the "Testing Effect" and how can a control group help mitigate it?
When the first measurement affects the second (practice/fatigue); a control group that takes the test without manipulation helps.
Distinguish between a "Construct" and its "Operationalization."
A construct is a theoretically defined variable (e.g., memory), while operationalization is how you measure it (e.g., words recalled).
Compare the advantages and disadvantages of "Convenience (Opportunity) Sampling."
Adv: Quick, easy, and cheap.
Disadv: Limited generalization due to sampling bias (e.g., psychology students).
Explain the technique of "Counterbalancing" and what it is meant to solve.
Reversing the order of trials for different groups (e.g., AB and BA) to control for order effects in repeated measures.
Why is there often an inverse relationship between internal and ecological validity?
High control (Internal) often requires artificial lab settings, which reduces how much the results apply to real-life (Ecological).
Describe "Selection Bias" and explain how random allocation prevents it.
Groups are not equivalent at the start; random allocation with large groups ensures differences cancel each other out.
Explain the "Nomothetic Approach" used in quantitative research.
It aims to derive universally applicable rules that can be applied to the behavior of large groups.
Discuss the limitations of "Self-Selected Sampling" regarding motivation and incentives.
Volunteers are often more motivated than the average person and may be pursuing monetary incentives, limiting representativeness.
Describe "Matched Pairs" design and the specific steps to implement it.
Participants are ranked on a matching variable (e.g., age), then randomly allocated into groups pairwise to ensure group equivalence.
Contrast a "True Experiment" with a "Quasi-Experiment" regarding cause-effect.
True: Random allocation allows for cause-effect inferences. Quasi: Grouped by pre-existing differences (e.g., gender), so cause-effect cannot be inferred.
Explain "Regression to the Mean" and when it becomes a threat to validity.
When initial scores are extreme, they naturally move toward the average over time; it's a threat when assessing training effectiveness.