Psychology Test 2 Review: Measurement, Reliability, Validity, Sampling, and Experimental Design

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. Describe and give examples of nominal, ordinal, interval, and ratio measures.

Background

Topic: Levels of Measurement

This question tests your understanding of the four main types of measurement scales used in psychological research and their characteristics.

Key Terms:

Nominal: Categories without order (e.g., gender, ethnicity).
Ordinal: Ordered categories, but intervals are not equal (e.g., ranking, Likert scales).
Interval: Ordered, equal intervals, no true zero (e.g., temperature in Celsius).
Ratio: Ordered, equal intervals, true zero (e.g., height, weight).

Step-by-Step Guidance

Start by defining each measurement scale and its properties.
Think of an example for each type that is relevant to psychology (e.g., nominal: diagnosis category; ordinal: symptom severity ranking).
Consider how data from each scale can be analyzed (e.g., nominal: frequency counts; ordinal: medians).
Reflect on why knowing the scale type is important for choosing statistical tests.

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Q2. Explain reliability and validity. How are they related? Are reliable measures always valid? Explain test-retest, equivalent forms, internal consistency, and interrater reliability. What is a good score for Cronbach’s alpha?

Background

Topic: Measurement Reliability and Validity

This question assesses your understanding of the concepts of reliability and validity in psychological measurement, their relationship, and specific types of reliability.

Key Terms:

Reliability: Consistency of a measure.
Validity: Accuracy of a measure.
Cronbach’s alpha: Internal consistency reliability coefficient.

Step-by-Step Guidance

Define reliability and validity, and discuss their relationship.
Explain why a reliable measure is not always valid (think about consistent but inaccurate measurements).
Describe each type of reliability: test-retest, equivalent forms, internal consistency, interrater reliability.
Identify what is considered a good Cronbach’s alpha score (usually above 0.7).

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Q3. Explain the types of validity. Explain content related, internal structure, and relation to other variables (predictive criterion, convergent, known groups, and discriminative).

Background

Topic: Types of Validity

This question tests your knowledge of different forms of validity and how they are assessed in psychological research.

Key Terms:

Content validity: Does the measure cover the construct?
Internal structure: Factor analysis, item relationships.
Criterion-related validity: Predictive, concurrent.
Convergent validity: Correlation with similar constructs.
Discriminant validity: No correlation with unrelated constructs.

Step-by-Step Guidance

List and define each type of validity.
Provide examples of how each type is assessed in research.
Explain the importance of each type for ensuring accurate measurement.
Consider how these types of validity relate to each other.

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Q4. Describe EPSEM. Describe Simple, Cluster, Systematic, and Proportional Stratified. How do you determine a good sample size?

Background

Topic: Sampling Methods

This question is about different probability sampling techniques and how to determine an appropriate sample size for a study.

Key Terms:

EPSEM: Equal Probability of Selection Method.
Simple random sampling: Every member has equal chance.
Cluster sampling: Groups sampled, not individuals.
Systematic sampling: Every nth member.
Proportional stratified sampling: Subgroups sampled proportionally.

Step-by-Step Guidance

Define EPSEM and its importance in sampling.
Describe each sampling method and give an example.
Discuss factors that influence sample size (e.g., population size, desired power, effect size).
Consider how to calculate or estimate a good sample size using statistical formulas.

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Q5. Define parameter and statistic and sampling error.

Background

Topic: Sampling and Estimation

This question tests your understanding of the difference between parameters and statistics, and the concept of sampling error.

Key Terms:

Parameter: Value describing a population.
Statistic: Value describing a sample.
Sampling error: Difference between statistic and parameter.

Step-by-Step Guidance

Define parameter and statistic, and explain their roles in research.
Describe how sampling error arises.
Consider why sampling error is important for interpreting results.
Think about ways to minimize sampling error.

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Q6. Describe nonrandom sampling. Include convenience, purposive, and snowball. Describe the different sampling approaches in qualitative research. Distinguish between random sampling and random assignment. Match them to internal or external validity.

Background

Topic: Sampling Methods and Validity

This question covers nonrandom sampling techniques, qualitative sampling, and the distinction between random sampling and random assignment.

Key Terms:

Convenience sampling: Using readily available participants.
Purposive sampling: Selecting participants for specific characteristics.
Snowball sampling: Participants recruit others.
Random sampling: Supports external validity.
Random assignment: Supports internal validity.

Step-by-Step Guidance

Define each nonrandom sampling method and provide examples.
Describe qualitative sampling approaches (e.g., theoretical, quota sampling).
Explain the difference between random sampling and random assignment.
Match each to the type of validity it supports.

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Q7. Explain statistical conclusion, construct, internal, and external validity.

Background

Topic: Types of Validity

This question tests your understanding of the four main types of validity in research.

Key Terms:

Statistical conclusion validity: Correctness of statistical inferences.
Construct validity: Accuracy of measurement of the construct.
Internal validity: Causal inference within the study.
External validity: Generalizability of findings.

Step-by-Step Guidance

Define each type of validity.
Provide examples of threats to each type.
Explain why each type is important for research conclusions.
Consider how to strengthen each type of validity.

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Q8. Describe participant reactivity effects. Include demand characteristics and positive self-presentation bias. Describe experimenter expectancy and experimenter attributes effect. Be able to identify extraneous confounding variables in examples.

Background

Topic: Threats to Validity

This question is about how participants and experimenters can influence research outcomes, and how to identify confounding variables.

Key Terms:

Participant reactivity: Changes in behavior due to awareness of being studied.
Demand characteristics: Cues that influence participant behavior.
Positive self-presentation: Participants try to look good.
Experimenter expectancy: Experimenter influences outcomes.
Experimenter attributes: Characteristics of experimenter affect results.
Extraneous/confounding variables: Uncontrolled variables that affect results.

Step-by-Step Guidance

Define participant reactivity and its subtypes.
Describe experimenter expectancy and attributes effects.
Explain how to identify extraneous and confounding variables in research scenarios.
Consider ways to control for these threats.

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Q9. Describe the threats to internal validity and the situations where they are a problem. Include history, maturation, testing, regression artifact, attrition, selection, and additive/interactive effects.

Background

Topic: Internal Validity

This question tests your knowledge of common threats to internal validity and when they are problematic.

Key Terms:

History: Events outside the study affect results.
Maturation: Changes due to time.
Testing: Effects of repeated testing.
Regression artifact: Extreme scores move toward the mean.
Attrition: Loss of participants.
Selection: Differences between groups.
Additive/interactive effects: Combined threats.

Step-by-Step Guidance

List and define each threat to internal validity.
Describe situations where each threat is likely to occur.
Explain how each threat can impact study results.
Consider strategies to minimize these threats.

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Q10. Describe the types of external validity (population, ecological, temporal, treatment variation, and outcome).

Background

Topic: External Validity

This question is about the different ways research findings can be generalized.

Key Terms:

Population validity: Generalization to other people.
Ecological validity: Generalization to other settings.
Temporal validity: Generalization across time.
Treatment variation validity: Generalization to other treatments.
Outcome validity: Generalization to other outcomes.

Step-by-Step Guidance

Define each type of external validity.
Provide examples of how each type can be threatened.
Explain why each type is important for generalizing findings.
Consider how to strengthen external validity.

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Q11. What is the trade-off between internal and external validity?

Background

Topic: Validity Trade-offs

This question is about the balance researchers must strike between controlling variables (internal validity) and generalizing findings (external validity).

Key Terms:

Internal validity: Control, causality.
External validity: Generalizability.

Step-by-Step Guidance

Explain what internal and external validity are.
Describe how increasing one can decrease the other.
Provide examples of studies with high internal but low external validity, and vice versa.
Consider strategies to balance both types of validity.

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Q12. What are the control techniques that can be used to strengthen research? What is the most powerful control technique? What does random assignment do?

Background

Topic: Experimental Control

This question is about methods researchers use to control extraneous variables and strengthen internal validity.

Key Terms:

Control techniques: Random assignment, matching, holding variables constant.
Random assignment: Assigning participants to groups by chance.

Step-by-Step Guidance

List and describe control techniques used in research.
Identify which technique is considered most powerful (random assignment).
Explain how random assignment strengthens internal validity.
Consider examples of how these techniques are applied.

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Q13. What are the strengths and weaknesses of matching? Describe the matching techniques – include their strengths and weaknesses.

Background

Topic: Control Techniques

This question is about matching participants in research to control for extraneous variables.

Key Terms:

Matching: Pairing participants based on characteristics.
Techniques: Individual matching, group matching.

Step-by-Step Guidance

Define matching and its purpose.
Describe individual and group matching techniques.
List strengths (e.g., controls for confounding variables) and weaknesses (e.g., time-consuming, may not control all variables).
Provide examples of when matching is useful.

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Q14. What should you do if you are interested in interactions between the IV and an extraneous variable?

Background

Topic: Experimental Design

This question is about how to study interactions between independent variables and extraneous variables.

Key Terms:

Interaction: Effect of one variable depends on another.
IV: Independent variable.
Extraneous variable: Uncontrolled variable.

Step-by-Step Guidance

Define what an interaction is in research.
Describe how to design a study to test for interactions (e.g., factorial design).
Explain how to analyze interactions statistically.
Consider examples of interactions in psychological research.

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Q15. Describe within participants and between participants designs. Describe order effects and carry over effects.

Background

Topic: Experimental Design

This question is about two main types of experimental designs and the issues that arise with repeated measures.

Key Terms:

Within participants design: Same participants in all conditions.
Between participants design: Different participants in each condition.
Order effects: Effects due to sequence of conditions.
Carry over effects: Effects from one condition influence another.

Step-by-Step Guidance

Define within and between participants designs.
Describe order and carry over effects.
Explain how these effects can threaten validity.
Consider ways to control for these effects.

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Q16. Describe counterbalancing. Know how to use the formula for complete and incomplete counterbalancing. What is differential carryover?

Background

Topic: Experimental Design Control

This question is about counterbalancing techniques to control for order effects in within-subjects designs.

Key Terms and Formulas:

Counterbalancing: Varying order of conditions.
Complete counterbalancing: All possible orders.
Formula for complete counterbalancing: (where is the number of conditions).
Incomplete counterbalancing: Subset of orders.
Differential carryover: Effects differ depending on order.

Step-by-Step Guidance

Define counterbalancing and its purpose.
Explain how to calculate the number of orders for complete counterbalancing using .
Describe incomplete counterbalancing and when it is used.
Define differential carryover and its implications.

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Q17. Describe the double-blind placebo method. Why would you use it? What is the purpose of automation in research?

Background

Topic: Experimental Control

This question is about methods to reduce bias in research.

Key Terms:

Double-blind: Neither participant nor experimenter knows condition.
Placebo: Inactive treatment.
Automation: Using technology to standardize procedures.

Step-by-Step Guidance

Define double-blind placebo method.
Explain why it is used (reduce bias).
Describe the purpose and benefits of automation in research.
Consider examples of automation.

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Q18. In a postexperimental interview – describe concurrent probing, sacrifice groups, and think-aloud.

Background

Topic: Postexperimental Procedures

This question is about methods used after an experiment to gather additional information from participants.

Key Terms:

Concurrent probing: Asking questions during the task.
Sacrifice groups: Groups used to test procedures.
Think-aloud: Participants verbalize thoughts.

Step-by-Step Guidance

Define each postexperimental interview technique.
Describe how each is used in research.
Explain the purpose of each technique.
Consider examples of their application.

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Q19. Describe the partial blind technique and automation. What are researcher attribute effects – how can automation help with these?

Background

Topic: Experimental Control

This question is about methods to reduce experimenter bias.

Key Terms:

Partial blind technique: Experimenter unaware of some conditions.
Automation: Standardizes procedures.
Researcher attribute effects: Experimenter characteristics influence outcomes.

Step-by-Step Guidance

Define partial blind technique and automation.
Describe researcher attribute effects.
Explain how automation can reduce these effects.
Consider examples of automation in research.

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Q20. Correlation/Causation - What can we conclude when two variables are correlated? What can we NOT conclude when two variables are correlated? Describe and identify Operational Definitions.

Background

Topic: Correlation vs. Causation and Operational Definitions

This question is about interpreting correlations and understanding operational definitions in research.

Key Terms:

Correlation: Relationship between variables.
Causation: One variable causes another.
Operational definition: How a variable is measured.

Step-by-Step Guidance

Explain what a correlation means and what it does not mean (causation).
Describe operational definitions and their importance.
Identify examples of operational definitions in psychological research.
Consider how operational definitions affect validity.

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Q21. Identify Mediating and Moderating Variables. What is a theory? Be able to evaluate the internal validity of studies using our 3 criteria (relationship, temporal order, rule out extraneous explanations).

Background

Topic: Variables and Internal Validity

This question is about different types of variables and how to evaluate internal validity.

Key Terms:

Mediating variable: Explains the relationship between IV and DV.
Moderating variable: Changes the strength/direction of relationship.
Theory: Set of principles explaining phenomena.
Internal validity criteria: Relationship, temporal order, rule out extraneous explanations.

Step-by-Step Guidance

Define mediating and moderating variables.
Describe what a theory is in psychology.
List and explain the three criteria for internal validity.
Provide examples of evaluating internal validity in studies.

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Q22. Essay Topic for Test 2 – Random Selection of Participants – what is it/how do you do it? Why is it important? What type of validity does it support? Why is it often difficult for research studies in psychology to have a randomly selected sample?

Background

Topic: Random Selection and Validity

This essay question is about the process and importance of random selection in research.

Key Terms:

Random selection: Every member of population has equal chance.
External validity: Supported by random selection.

Step-by-Step Guidance

Define random selection and describe how it is done.
Explain why random selection is important for research.
Identify the type of validity it supports (external validity).
Discuss challenges in achieving random selection in psychology studies.