DEPENDENT VARIABLE. TEST UNITS - subjects or entities whose response to the experimental treatment are measured or observed. Dependent Variable

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1 EXPERIMENT Experimental Research A 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 Basic Issues of Experimental Design Manipulation of Independent Variables Manipulation of the Independent Variable Selection of Dependent Variable Assignment of Subjects (or other Test Units) Control Over Extraneous Variables Classificatory Vs. Continuous Variables Experimental and Control Groups Treatment Levels More Than One Independent Variable

2 DEPENDENT VARIABLE Experimental treatments are the alternative manipulations of the independent variable being investigated. Its value is expected to be dependent on the experimenter s manipulation Criterion or standard by which the results are judged Dependent Variable Selection - e.g., sales volume, awareness, recall TEST UNITS - subjects or entities whose response to the experimental treatment are measured or observed. Measurement

3 Two Types of Experimental Error Controlling Extraneous Variables Constant Error Random Errors Elimination of Extraneous Variables Constancy of Conditions Order of Presentation Blinding Random Assignment DEMAND CHARACTERISTICS Demand Characteristics EXPERIMENTAL PROCEDURES THAT INTENTIONALLY HINT TO SUBJECTS SOMETHING ABOUT THE EXPERIMENTER S HYPOTHESIS Guinea Pigs Hawthorne Effect

4 Field vs. Laboratory Experiment Laboratory Experiment Artificial-Low Realism Few Extraneous Variables High control Low Cost Short Duration Subjects Aware of Participation Field Experiment Natural-High Realism Many Extraneous Variables Low control High Cost Long Duration Subjects Unaware of Participation WHEN IS AN EXPERIMENT INTERNAL VALIDITY? Factors Influencing Internal Validity INTERNAL VALIDITY Confidence that the only cause of change in the dependent variable came because of a change in the independent variable. Did the manipulation do what it was supposed to do? History Maturation Testing Instrumentation Selection Mortality

5 Type of Extraneous Variable History - specific events in the Environment between the Before and After Measurement That Are beyond the Experimenter s Control Example A Major Employer Closes Its Plant in Test Market Area Other Factors Instrument - Changes in Instrument Result in Response Bias Example New Questions about Women are Interpreted Differently from Earlier Questions. Maturation - subjects Change during the Course of the Experiment Testing - The Before Measure Alerts or Sensitizes Subject to Nature of Experiment or Second Measure. Subjects Become Tired Questionnaire about the Traditional Role of Women Triggers Enhanced Awareness of Women in an Experiment. Selection - Sample Selection Error Because of Differential Selection Comparison Groups Mortality - Sample Attrition; some Subjects Withdraw from Experiment Control Group and Experimental Group Is Self-Selected Group Based on Preference for Soft Drinks Subjects in One Group of a Hair Dying Study Marry Rich Widows and move to Florida Increasing Internal Validity HOW CAN INTERNAL VALIDITY BE INCREASE? Control Group Random Assignment Pretesting and Posttesting Posttest Only

6 Quasi-Experimental Designs WHAT ARE THE DIFFERENT BASIC EXPERIMENTAL DESIGNS? One Shot Design (After Only) One Group Pretest-Posttest Static Group Design ONE SHOT DESIGN (AFTER ONLY) X O 1 One Group Pretest -Posttest O 1 X O 2

7 Three Good Experimental Designs Static Group Design Experimental Group X O 1 Control Group O 2 Pretest - Posttest Control Group Design Posttest Only Control Group Solomon Four Group Design Pretest -Posttest Control Group Design Experimental Group R O 1 X O 2 Control Group R O 3 X O 4 Posttest Only Control Group Experimental Group R X O 1 Control Group R O 2

8 TEST MARKETING Solomon Four Group Design Experimental Group 1: R O 1 X O 2 Control Group 1: R O 3 O 4 Experimental Group 2: R X O 5 Control Group 2: R X O 6 EXPERIMENTAL PROCEDURE OPPORTUNITY TO TEST A NEW PRODUCT NEW MARKETING PLAN UNDER REALISTIC MARKET CONDITIONS MEASURE SALES OR PROFIT POTENTIAL. SELECTING A TEST MARKET CONTROL METHOD OF TEST MARKETING POPULATION SIZE DEMOGRAPHIC COMPOSITION LIFESTYLE CONSIDERATIONS COMPETITIVE SITUATION MEDIA SELF -CONTAINED TRADING AREA SECRECY SMALL CITY LOW CHANCE OF BEING DETECTED DISTRIBUTION IS FORCED (GUARANTEED)

9 ADVANCED EXPERIMENTAL DESIGNS ARE MORE COMPLEX COMPLETELY RANDOMIZED RANDOMIZED BLOCK DESIGN LATIN SQUARE FACTORIAL