- 1. Exploring Marketing Research William G. Zikmund Chapter 11:
Experimental Research
- 2. ExperimentA research investigation in which conditions are controlled
One independent variable is manipulated (sometimes more than one)
Its effect on a dependent variable is measured
To test a hypothesis
- 3. Manipulation of the Independent Variable
Selection of Dependent Variable
Assignment of Subjects (or other Test Units)
Control Over Extraneous VariablesBasic Issues of Experimental Design
- 4. Experiment TreatmentAlternative manipulations of the independent variable being investigated
- 5. Independent VariableThe experimenter controls independent variable.
The variable’s value can be manipulated by the experimenters to whatever they wish it to be.
- 6. Manipulation of Independent VariableClassificatory vs. Continuous Variables
Experimental and Control Groups
Treatment Levels
More Than One Independent Variable
- 7. Dependent VariableIts value is expected to be dependent on the experimenter’s manipulation
Criterion or standard by which the results are judged
- 8. TEST UNITS - subjects or entities whose response to the experimental treatment are measured or observed.
- 9. Controlling Extraneous VariablesElimination of Extraneous Variables
Constancy of Conditions
Order of Presentation
Blinding
Random Assignment
- 10. How May an Experimenter control for
Extraneous Variation?Eliminate Extraneous Variables
Hold Conditions Constant
Randomization
Matching Subjects
- 11. Demand CharacteristicsExperimental procedures that intentionally hint to subjects something about the experimenter’s hypothesis
- 12. Laboratory ExperimentField ExperimentArtificial-Low RealismFew Extraneous
VariablesHigh controlLow CostShort DurationSubjects Aware of
ParticipationNatural-High RealismMany Extraneous
VariablesLow controlHigh CostLong DurationSubjects Unaware of
Participation*
Copyright © 2000 by Harcourt, Inc. All rights reserved.
- 13. Control Groups Isolates Extraneous Variation
- 14. When does an Experiment have Internal Validity?Internal Validity - The ability of an experiment to answer the question whether the experimental treatment was the sole cause of changes in a dependent variable
Did the manipulation do what it was supposed to do?
- 15. Factors Influencing Internal Validity History
Maturation
Testing
Instrumentation
Selection
Mortality
- 16. Isolating Extraneous Variation
with a Control Group History Effects
Maturation Effects
Mortality Effects
- 17. Increasing Internal Validity Control Group
Random Assignment
Pretesting and Posttesting
Posttest Only
- 18. Quasi-Experimental Designs One Shot Design (After Only)
One Group Pretest-Posttest
Static Group Design
- 19. One Shot Design (After Only)
X O1
- 20. One Group Pretest-Posttest
O1 X O2
- 21. Static Group Design
Experimental Group X O1
Control Group O2
- 22. Three Good Experimental Designs Pretest - Posttest Control Group Design
Posttest Only Control Group
Solomon Four Group Design
- 23. Pretest-Posttest Control Group DesignExperimental Group R O1 X O2
Control Group R O3 X O4
- 24. Posttest Only Control GroupExperimental Group R X O1
Control Group R O2
