Chapter 8: Experimental design

Question 1

What is a “true” experiment?

Answer 1

• Has experimental group and control group
• Manipulates only one independent variable

Question 2

Dependent Variable
(definition)

Answer 2

• A variable affected or expected to be affected by independent variables
• The outcome variable

Question 3

Operational Definition
(definition)

Answer 3

Defining a term by stating the actions, processes, or operations used to measure or identify examples of it. Such as “achievements” would be defined as high grades, or good communications

Question 4

Independent Variable
(definition)

Answer 4

A variable that affects the dependent variable under study and is included in the research design so that its effect can be determined

Question 5

Confounding Variable
(definition)

Answer 5

• An uncontrolled variable
• Cannot attribute observed effects to confounding or independent variable

Question 6

“Good” Internal validity
(definition)

Answer 6

• Experiment results confidently attributed to independent variable
• Accuracy of conclusions

Question 7

How is internal validity maintained in an experiment?

Answer 7

Balancing the groups

• groups are basically equal
• participants are randomly assigned to a group

Holding conditions constant

• conditions are constant between groups
• only difference is the independent variable being manipulated

Question 8

What are the advantages/disadvantages of Pretest-Posttest design?

Answer 8

Advantages

• could help balance groups
• in case ppl drop out (attrition), have initial data that may explain

Disadvantages

• might reveal to participants the purpose of the experiment
• they might detect the dependent variable

Note: With a large enough sample, random assignment will produce nearly identical groups