1. Chapter 12 Experimental Research © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. EIGHTH EDITION BUSINESS MARKET RESEARCH ZIKMUND BABIN CARR GRIFFIN

2. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–2 LEARNING OUTCOMES 1.Identify the independent variable, dependent variable, and construct a valid simple experiment to assess a cause and effect relationship 2.Understand and minimize experimental error 3.Know ways of minimizing experimental demand characteristics 4.Avoid unethical experimental practices After studying this chapter, you should be able to

3. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–3 LEARNING OUTCOMES (cont’d) 5.Understand the advantages of a between- subjects experimental design 6.Weigh the trade-off between internal and external validity 7.Use manipulations to implement a completely randomized experimental design, a randomized-block design, and a factorial experimental design After studying this chapter, you should be able to

4. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–4 Creating an Experiment SubjectsSubjects  The sampling units for an experiment, usually human respondents who provide measures based on the experimental manipulation. Independent VariablesIndependent Variables  Experimental conditions  One of the possible levels of an experimental (independent) variable manipulation.  Blocking variables  Variables included in the statistical analysis as a way of controlling or accounting for variance due to that variable:  Categorical variables

5. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–5 EXHIBIT 12.1 Experimental Conditions in Self-Efficacy Experiment

6. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–6 Creating an Experiment (cont’d) Main EffectMain Effect  The experimental difference in dependent variable means between the different levels of any single experimental variable. Interaction EffectInteraction Effect  Differences in dependant variable means due to a specific combination of independent variables.

7. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–7 EXHIBIT 12.2 Job Satisfaction Means in Self-Efficacy Experiment

8. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–8 EXHIBIT 12.3 Experimental Graph Showing Results within Each Condition

9. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–9 Designing an Experiment to Minimize Experimental Error Manipulation of the Independent VariableManipulation of the Independent Variable  Experimental treatment: the way an experimental variable is manipulated.  Categorical variables: described by class or quality  Continuous variables: described by quantity (level)  Experimental Group  A group of subjects to whom an experimental treatment is administered.  Control Group  A group of subjects to whom no experimental treatment is administered.

10. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–10 Designing an Experiment (cont’d) More than One Independent VariableMore than One Independent Variable  Cell: a specific treatment combination associated with an experimental group.  Computation of the number of cells in an experiment: K = (T 1 )(T 2 )..(T m ) Repeated MeasuresRepeated Measures  Experiments in which an individual subject is exposed to more than one level of an experimental treatment.

11. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–11 Designing an Experiment (cont’d) Selection and Measurement of the Dependent VariableSelection and Measurement of the Dependent Variable  Selecting dependent variables that are relevant and truly represent an outcome of interest is crucial.  Choosing the right dependent variable is part of the problem definition process.  Thorough problem definition will help the researcher select the most important dependent variable(s).

12. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–12 Designing an Experiment (cont’d) Selection and Assignment of Test UnitsSelection and Assignment of Test Units  Test units: the subjects or entities whose responses to treatment are measured or observed. Sample Selection And Random Sampling ErrorsSample Selection And Random Sampling Errors  Systematic or nonsampling error  Subject selection, experimental design, and unrecognized extraneous variables  Overcoming sampling errors  Randomization  Matching  Control over extraneous variables

13. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–13 Designing an Experiment (cont’d) Sample Selection And Random Sampling ErrorsSample Selection And Random Sampling Errors  Experimental Confound  When there is an alternative explanation beyond the experimental variables for any observed differences in the dependent variable.  Once a potential confound is identified, the validity of the experiment is severely questioned.  Extraneous variables  Variables that naturally exist in the environment that may have some systematic effect on the dependent variable.

14. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–14 Demand Characteristics Demand CharacteristicDemand Characteristic  An experimental design element or procedure that unintentionally provides subjects with hints about the research hypothesis. Demand EffectDemand Effect  Occurs when demand characteristics actually affect the dependent variable. Hawthorne EffectHawthorne Effect  People will perform differently from normal when they know they are experimental subjects.

15. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–15 Reducing Demand Effects

16. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–16 Establishing Control Constancy of ConditionsConstancy of Conditions  Subjects in all experimental groups are exposed to identical conditions except for the differing experimental treatments. CounterbalancingCounterbalancing  Attempts to eliminate the confounding effects of order of presentation by varying the order of presentation (exposure) of treatments to subject groups.

17. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–17 Ethical Issues in Experimentation Debriefing experimental subjectsDebriefing experimental subjects  Communicating the purpose of the experiment  Explaining the researcher’s hypotheses Attempts to interfere with a competitor’s test- marketing effortsAttempts to interfere with a competitor’s test- marketing efforts  Such acts as changing prices or increasing advertising to influence (confound) competitors’ test- marketing results are ethically questionable.

18. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–18 Practical Experimental Design Issues Basic versus Factorial Experimental DesignsBasic versus Factorial Experimental Designs  Basic experimental designs – a single independent variable and a single dependent variable.  Factorial experimental design – allows for an investigation of the interaction to two or more independent variables. Laboratory ExperimentLaboratory Experiment  A situation in which the researcher has more complete control over the research setting and extraneous variables. Field ExperimentsField Experiments  Research projects involving experimental manipulations that are implemented in a natural environment.

19. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–19 EXHIBIT 12.5 The Artificiality of Laboratory versus Field Experiments

20. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–20 Within-Subjects and Between-Subjects Designs Within-Subjects DesignWithin-Subjects Design  Involves repeated measures because with each treatment the same subject is measured. Between-Subjects DesignBetween-Subjects Design  Each subject receives only one treatment combination.  Usually advantageous although they are usually more costly.  Validity is usually higher.

21. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–21 EXHIBIT 12.6 Within- and Between- Subjects Designs

22. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–22 Issues of Experimental Validity Internal ValidityInternal Validity  The extent that an experimental variable is truly responsible for any variance in the dependent variable.  Does the experimental manipulation truly cause changes in the specific outcome of interest? Manipulation ChecksManipulation Checks  A validity test of an experimental manipulation to make sure that the manipulation does produce differences in the independent variable.

23. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–23 Extraneous Variables Affecting Internal Validity Internal Validity MaturationMaturation TestingTesting InstrumentationInstrumentationSelectionSelection MortalityMortality HistoryHistory

24. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–24 Effects of Extraneous Variables on Validity History EffectHistory Effect  Occurs when some change other than the experimental treatment occurs during the course of an experiment that affects the dependent variable.  Cohort Effect  A change in the dependent variable that occurs because members of one experimental group experienced different historical situations than members of other experimental groups.

25. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–25 Effects of Extraneous Variables… (cont’d) Maturation EffectsMaturation Effects  Effects that are a function of time and the naturally occurring events that coincide with growth and experience. Testing effectsTesting effects  A nuisance effect occurring when the initial measurement or test alerts or primes subjects in a way that affects their response to the experimental treatments.

26. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–26 Effects of Extraneous Variables… (cont’d) Instrumentation EffectInstrumentation Effect  A change in the wording of questions, a change in interviewers, or a change in other procedures causes a change in the dependent variable. SelectionSelection  The selection effect is a sample bias that results from differential selection of respondents for the comparison groups, or a sample selection error. Mortality Effect (Sample Attrition)Mortality Effect (Sample Attrition)  Occurs when some subjects withdraw from the experiment before it is completed.

27. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–27 Extraneous Variables History Uncontrollable events occurring in the environment between before and after measurements Maturation Changes in subjects during the course of the experiment Testing A before measure that alerts or sensitizes subject to the nature of experiment or second measure. A major employer closes its plant in test market area. Subjects become tired during the experiment. A questionnaire about the traditional role of women triggers enhanced awareness of females in an experiment. Extraneous VariableExample

28. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–28 Extraneous Variables (cont’d) Instrument – Changes in instrument result in response bias Selection Sample selection error because of differential selection comparison groups Mortality Sample attrition; some subjects withdraw from experiment New questions about women are interpreted differently from earlier questions. 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 Extraneous VariableExample

29. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–29 Issues of Experimental Validity (cont’d) External ValidityExternal Validity  The accuracy with which experimental results can be generalized beyond the experimental subjects.  Student surrogates: Atypical? Trade-Offs Between Internal and External ValidityTrade-Offs Between Internal and External Validity  Artificial laboratory experiments usually are high in internal validity, while naturalistic field experiments generally have less internal validity, but greater external validity.

30. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–30 Laboratory Experiment Field Experiment Artificial: Low Realism Few Extraneous Variables Variables High control Low Cost Short Duration Subjects Aware of Participation Participation Natural: High Realism Many Extraneous Variables Variables Low control High Cost Long Duration Subjects Unaware of Participation Participation Laboratory versus Field Experiments

31. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–31 Classification of Experimental Designs Basic Experimental DesignBasic Experimental Design  An experimental design in which only one variable is manipulated. Diagramming Experimental Designs: SymbolsDiagramming Experimental Designs: Symbols

32. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–32 Examples of Quasi-Experimental Designs Quasi-experimental DesignsQuasi-experimental Designs  Experimental designs that do not involve random allocation of subjects to treatment combinations. One Shot Design (After Only):XO 1One Shot Design (After Only):XO 1 One Group Pretest–Posttest:O 1 XO 2One Group Pretest–Posttest:O 1 XO 2 Static Group Design:ExperimentalXO 1 ControlO 2Static Group Design:ExperimentalXO 1 ControlO 2

33. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–33 Alternative Experimental Designs Pretest–Posttest Control Group Design (Before–After with Control)Pretest–Posttest Control Group Design (Before–After with Control)  ExperimentalR O 1 X O 2  ControlR O 3 X O 4  ControlR O 3 X O 4 Posttest Only Control Group (After-Only with Control)Posttest Only Control Group (After-Only with Control)  ExperimentalR X O 1  ControlR O 2

34. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–34 EXHIBIT 12.7 Product Preference Measure in an Experiment

35. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–35 EXHIBIT 12.8 Selected Time Series Outcomes

36. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–36 Complex Experimental Designs Completely Randomized Design Randomized Block Design Factorial

37. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–37 Complex Experimental Designs (cont’d) Completely Randomized DesignCompletely Randomized Design  An experimental design that uses a random process to assign subjects (test units) to treatment levels to investigate the effects of an experimental variable.

38. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–38 Complex Experimental Designs (cont’d) Randomized Block DesignRandomized Block Design  An extension of the completely randomized design in which a single categorical extraneous variable that might affect test units’ responses to the treatment is identified and the effects of this variable are isolated by being blocked out. Blocking VariableBlocking Variable  A categorical variable that is expected to be associated with different values of a dependent variable for each group. It effectively controls for an extraneous cause in experimental analysis.

39. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–39 EXHIBIT 12.9 Randomized Block Design

40. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–40 Complex Experimental Designs (cont’d) Factorial DesignFactorial Design  An experiment that investigates the interaction of two or more independent variables on a single dependent variable.

41. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–41 EXHIBIT 12.10 Factorial Design—Salary and Vacation

42. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–42 Effects in Factorial Design Main effectMain effect  The influence of a single independent variable on a dependent variable. Interaction effectInteraction effect  The influence on a dependent variable by combinations of two or more independent variables.  Interaction occurs if the effect of one treatment differs at various levels of the other treatment.

43. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–43 EXHIBIT 12.11 A 2 × 2 Factorial Design That Illustrates the Effects of Sex and Ad Content on Believability

44. © 2010 South-Western/Cengage Learning. All rights reserved. May not be scanned, copied or duplicated, or posted to a publically accessible website, in whole or in part.12–44 EXHIBIT 12.12 Graphic Illustration of Interaction between Gender and Advertising Copy