Chapter 8: Two-Group Experimental Design and Analysis

What is the primary goal of experimental design?

To identify cause-and-effect relationships between variables.

What are the three criteria for establishing a cause-and-effect relationship?

Covariation, temporal precedence, and elimination of extraneous variables.

What does covariation indicate?

It shows that changes in one variable are associated with changes in another variable.

What is temporal precedence?

It means that changes in the suspected cause occur before changes in the effect.

Why is it important to eliminate extraneous variables?

To increase internal validity and rule out other possible causal explanations.

What is a two-group design?

An experimental design that compares two groups or conditions to establish cause and effect.

What is the experimental group?

The group that receives the key treatment in an experiment.

What is the control group?

The condition that serves as a comparison group in an experiment.

What is an all-or-nothing comparison in experimental design?

A comparison where the independent variable is either present or absent.

What is a behavioral measure?

A measure of participants' actions in a research design.

What are the pros of self-report measurement?

Easy to administer, cost-effective, and provides first-hand information.

What are the cons of self-report measurement?

Potential inaccuracies due to self-knowledge, social desirability, and retrospective bias.

What is participant reactivity?

When participants act differently because they know they are being observed.

What is an experimental hypothesis?

A clear and specific prediction of how the independent variable will influence the dependent variable.

What is the difference between a directional and nondirectional hypothesis?

A directional hypothesis makes a specific prediction, while a nondirectional hypothesis does not.

What is random assignment in experimental design?

A method that ensures each participant has an equal chance of being in any group.

What is a matched-pair design?

A design where participants are paired based on a key trait and then randomly assigned to different groups.

What is a manipulation check?

A measure that helps determine whether the manipulation effectively changed the independent variable.

What is an independent samples t-test?

A statistical test comparing means of two independent groups to see if they differ significantly.

What is a paired-sample t-test?

A statistical test comparing means of the same group at different times or conditions.

What does the p-value indicate in hypothesis testing?

The likelihood that the observed difference occurred by chance.

What is effect size?

The magnitude of the difference between groups.

What should be included in the results section of a study?

Findings, manipulation checks, and analyses of alternate explanations.

What does it mean if a manipulation check is significant?

It suggests that the manipulation was effective in changing the independent variable.

How can you determine if cell phone restriction influences quiz scores?

By conducting a t-test for independent means comparing scores between high- and low-restriction groups.