Chapter 9 Research Methodology: Sampling and Experimental Design

What is Probability Sampling?

A method where each member of the population has a known chance of being selected, ideal for generalizability.

What is Nonprobability Sampling?

A method where participants are selected based on convenience or judgment, suitable for hypothesis testing.

How does sample size affect statistical significance?

Larger sample sizes increase the likelihood of detecting statistically significant effects, improving reliability and power.

What is the importance of informed consent in experiments?

Participants must be fully informed to maintain engagement and ethical standards.

What are Straightforward Manipulations?

Direct instructions, stimuli, or information used in experiments, easier to administer and less costly.

What are Staged Manipulations?

Manipulations that create psychological states or simulate real-world events, often involving confederates.

What is the balance required in manipulation strength?

Stronger manipulations can have larger effects but must avoid being unrealistic or unethical; weaker manipulations may not detect an effect.

What are the costs associated with different types of manipulations?

Straightforward manipulations are less costly, while staged manipulations may require confederates, props, or special environments.

What are the types of measures for the dependent variable (DV)?

Self-report, behavioral observation, and physiological measures (e.g., GSR, EMG, EEG, MRI/fMRI).

Why is using multiple measures for the DV beneficial?

It enhances confidence in results and helps mitigate order effects.

What are the Ceiling and Floor Effects?

Ceiling Effect occurs when a task is too easy, leading most to score at the top; Floor Effect occurs when a task is too hard, leading most to score at the bottom.

What are the costs of different measures?

Self-reports are cheap and easy, while behavioral and physiological measures are often more expensive and require equipment or trained observers.

What are Demand Characteristics?

Cues that suggest the study's purpose, which can influence participant behavior.

How can Demand Characteristics be mitigated?

Through deception, filler items, or unrelated questions.

What are Placebo Effects?

Improvements due to participants' belief in the treatment, controlled by using a placebo group.

What are Expectancy Effects?

Unintentional influences by the researcher on outcomes, such as tone of voice or body language.

What controls can be used to minimize Expectancy Effects?

Training for consistency, running all conditions simultaneously, using automated procedures, and employing single-blind or double-blind designs.

What is a Research Proposal?

A written plan that justifies and outlines the study design.

What is the purpose of Pilot Studies?

To conduct small-scale trial runs that help refine procedures, instructions, and measures.

What are Manipulation Checks?

Measures to confirm that the independent variable produced the intended psychological state.

What is the purpose of Debriefing?

To provide a post-experiment explanation to participants, especially important after deception.

What is Preregistration in research?

The practice of publicly posting hypotheses, methods, and analysis plans before collecting data to promote transparency.

What should researchers analyze to interpret results?

Appropriate statistical analyses to determine if the independent variable affected the dependent variable, looking for patterns, effect sizes, and significance.

What are professional meetings and peer-reviewed journals used for in research?

Professional meetings are for presenting findings, while peer-reviewed journals require submissions to undergo peer review, often with high rejection rates.