Marketing ResearchExperimentA research investigation in which conditions are controlledOne independent variable is manipulated (sometimes more than one)Its effect on a dependent variable is measuredTo test a hypothesisManipulation of the Independent VariableSelection of Dependent VariableAssignment of Subjects (or other Test Units)Control Over Extraneous VariablesBasic Issues of Experimental DesignExperiment TreatmentAlternative manipulations of the independent variable being investigatedIndependent VariableThe experimenter controls independent variable.The variables value can be manipulated by the experimenters to whatever they wish it to be.Manipulation of Independent VariableClassificatory vs. Continuous VariablesExperimental and Control GroupsTreatment LevelsMore Than One Independent VariableDependent VariableIts value is expected to be dependent on the experimenters manipulationCriterion or standard by which the results are judgedTEST UNITS - subjects or entities whose response to the experimental treatment are measured or observed.Controlling Extraneous VariablesElimination of Extraneous VariablesConstancy of ConditionsOrder of PresentationBlindingRandom AssignmentHow May an Experimenter control forExtraneous Variation?Eliminate Extraneous VariablesHold Conditions ConstantRandomizationMatching SubjectsDemand CharacteristicsExperimental procedures that intentionally hint to subjects something about the experimenters hypothesisLaboratory ExperimentField ExperimentArtificial-Low RealismFew ExtraneousVariablesHigh controlLow CostShort DurationSubjects Aware ofParticipationNatural-High RealismMany ExtraneousVariablesLow controlHigh CostLong DurationSubjects Unaware ofParticipationControl Groups Isolates Extraneous VariationWhen 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 variableDid the manipulation do what it was supposed to do?Factors Influencing Internal Validity History Maturation Testing Instrumentation Selection MortalityIsolating Extraneous Variationwith a Control Group History Effects Maturation Effects Mortality EffectsIncreasing Internal Validity Control Group Random Assignment Pretesting and Posttesting Posttest OnlyQuasi-Experimental Designs One Shot Design (After Only) One Group Pretest-Posttest Static Group DesignOne Shot Design (After Only)XO1One Group Pretest-PosttestO1X O2Static Group Design Experimental GroupX O1 Control Group O2Three Good Experimental Designs Pretest - Posttest Control Group Design Posttest Only Control Group Solomon Four Group DesignPretest-Posttest Control Group DesignExperimental Group R O1 X O2Control Group R O3 X O4 Posttest Only Control GroupExperimental Group R X O1Control Group R O2