Final Exam Study Guide: Research Methodology and Design

What is the difference between probability sampling and non-probability sampling?

Probability sampling involves random selection from a population, while non-probability sampling does not use random selection.

What are the advantages of simple random sampling?

It ensures that every individual has an equal chance of being selected, reducing bias.

What is stratified sampling?

A method where participants are randomly selected in proportion to the demographics of the population.

What is convenience sampling?

Selecting a sample based on ease of access rather than random selection.

What is the purpose of random assignment in research?

To ensure that groups are probabilistically equal, allowing for causal inferences.

What are the disadvantages of non-random assignment?

It weakens causal inference as groups may differ systematically.

What is the role of an independent variable (IV) in an experiment?

The IV is manipulated to examine its effect on the dependent variable (DV).

Why are controls important in research?

Controls mitigate outside variables that could weaken the study's inferences.

What characterizes a randomized experiment?

It has strict controls, random assignment, and can establish causation.

What is a quasi-experiment?

Similar to an experiment but lacks random assignment, making it less able to establish causation.

What distinguishes non-experimental research?

It cannot examine causation but is useful for exploring relationships between variables.

Define internal validity.

The validity of causal inferences made from the results of a study.

Define external validity.

The generalizability of the results of a study to other settings or populations.

What is ambiguous temporal precedence?

Uncertainty about which variable occurred first, complicating causal interpretations.

What is selection bias in research?

Systematic differences in respondent characteristics across conditions that could affect outcomes.

What is maturation

Naturally occurring changes over time that could be mistaken for treatment effects.

What is regression to the mean?

The phenomenon where extreme scores tend to be less extreme upon retesting.

How does attrition affect research validity?

Loss of participants can create biases if the loss is correlated with treatment conditions.

What is the testing threat to internal validity?

Exposure to a test may influence scores on subsequent tests, confounding results.

What is instrumentation in research?

Changes in the measurement process over time that could affect results.

What is meant by context-dependent mediation?

A mediator may explain a causal relationship in one context but not in another.

What is the difference between within-subjects and between-subjects designs?

Within-subjects design has individuals experience all levels of the IV, while between-subjects design has individuals experience only one level.

What is a factorial experimental design?

A design with multiple independent variables (IVs), each having different levels.

What does a 3x2 factorial design indicate?

It has two factors, one with three levels and one with two levels.

What are main effects in experimental design?

Changes directly resulting from a single factor.

What are interactions in experimental design?

Changes in one factor that differ based on the effect of another factor.

What is a mixed design in research?

A combination of both between-subjects and within-subjects designs.