Business Research Methods, 9th ed.Chapter 12

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William G. Zikmund, Barry J. Babin, Jon C. Carr, Mitch Griffin

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Business Research Methods, 9th ed.Chapter 12

  1. 1. Business Research Methods William G. Zikmund Chapter 12: Experimental Research
  2. 2. Experiment • 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
  3. 3. Basic Issues of Experimental Design • Manipulation of the Independent Variable • Selection of Dependent Variable • Assignment of Subjects (or other Test Units) • Control Over Extraneous Variables
  4. 4. The experimenter has some degree of control over the independent variable. The variable is independent because its value can be manipulated by the experimenter to whatever he or she wishes it to be.
  5. 5. Experiment Treatment Alternative manipulations of the independent variable being investigated
  6. 6. Independent Variable • The experimenter controls independent variable. • The variable’s value can be manipulated by the experimenters to whatever they wish it to be.
  7. 7. Manipulation of Independent Variable • Classificatory Vs. continuous variables • Experimental and control groups • Treatment levels • More than one independent variable
  8. 8. Experimental Treatments • The alternative manipulations of the independent variable being investigated
  9. 9. Dependent Variable • Its value is expected to be dependent on the experimenter’s manipulation • Criterion or standard by which the results are judged
  10. 10. Dependent Variable • Selection –e.g... sales volume, awareness, recall, • Measurement
  11. 11. Test Units • Subjects or entities whose response to the experimental treatment are measured or observed.
  12. 12. Two Types of Experimental Error • Constant errors • Random errors
  13. 13. Field versus Laboratory Experiments
  14. 14. Controlling Extraneous Variables • Elimination of extraneous variables • Constancy of conditions • Order of presentation • Blinding • Random assignment
  15. 15. How May an Experimenter control for Extraneous Variation? • Eliminate Extraneous Variables • Hold Conditions Constant • Randomization • Matching Subjects
  16. 16. Establishing Control
  17. 17. Demand Characteristics • Experimental procedures that intentionally hint to subjects something about the experimenter’s hypothesis
  18. 18. Demand Characteristics • Guinea pig effect • Hawthorne effect
  19. 19. Field Vs. Laboratory Experiment
  20. 20. Laboratory Experiment Field Experiment Artificial-Low Realism Few Extraneous Variables High control Low Cost Short Duration Subjects Aware of Participation Natural-High Realism Many Extraneous Variables Low control High Cost Long Duration Subjects Unaware of Participation
  21. 21. Control Groups Isolate extraneous variation
  22. 22. 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?
  23. 23. Factors Influencing Internal Validity • History • Maturation • Testing • Instrumentation • Selection • Mortality
  24. 24. Isolating Extraneous Variation with a Control Group • History Effects • Maturation Effects • Mortality Effects
  25. 25. Type of Extraneous Variable Example History - Specific events in the environment between the Before and After measurement that are beyond the experimenter’s control Maturation - Subjects change during the course of the experiment Testing - The Before measure alerts or sensitizes subject to nature of experiment or second measure. A major employer closes its plant in test market area Subjects become tired Questionnaire about the traditional role of women triggers enhanced awareness of women in an experiment.
  26. 26. 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
  27. 27. How can Internal Validity Increase?
  28. 28. Increasing Internal Validity • Control group • Random assignment • Pretesting and posttesting • Posttest only
  29. 29. What are the Different Basic Experimental Designs?
  30. 30. Quasi-Experimental Designs • One Shot Design (After Only) • One Group Pretest-Posttest • Static Group Design
  31. 31. One Shot Design (After Only) X O1
  32. 32. One Group Pretest-Posttest O1 X O2
  33. 33. Static Group Design Experimental Group X O1 Control Group O2
  34. 34. Three Good Experimental Designs • Pretest - Posttest Control Group Design • Posttest Only Control Group • Solomon Four Group Design
  35. 35. Pretest-Posttest Control Group Design Experimental Group R O1 X O2 Control Group R O3 X O4
  36. 36. Posttest Only Control Group Experimental Group R X O1 Control Group R O2
  37. 37. One-Shot Design Internal Validity Problems • History – weak • Maturation – weak • Testing – not relevant • Instrumentation – not relevant • Selection – weak • Mortality – weak
  38. 38. One-Group Pretest-Posttest Internal Validity Problems • History – weak • Maturation – weak • Testing – weak • Instrumentation – weak • Selection – controlled • Mortality – controlled
  39. 39. Static-Group Design Internal Validity Problems • History – controlled • Maturation – possible source of concern • Testing – controlled • Instrumentation – controlled • Selection – weak • Mortality – weak
  40. 40. Pretest-Posttest Control Internal Validity Problems • History – controlled • Maturation – controlled • Testing – controlled • Instrumentation – controlled • Selection – controlled • Mortality – controlled
  41. 41. Solomon Four-Group Design Internal Validity Problems • History – controlled • Maturation – controlled • Testing – controlled • Instrumentation – controlled • Selection – controlled • Mortality – controlled
  42. 42. Posttest-Only Control Internal Validity Problems • History – controlled • Maturation – controlled • Testing – controlled • Instrumentation – controlled • Selection – controlled • Mortality – controlled
  43. 43. Solomon Four Group Design Experimental Group 1: R O1 X O2 Control Group 1: R O3 O4 Experimental Group 2: R X O5 Control Group 2: R X O6
  44. 44. Advanced Experimental Designs are More Complex • Completely randomized • Randomized block design • Latin square • Factorial
  45. 45. Completely Randomized Design • An experimental design that uses a random process to assign subjects (test units) and treatments to investigate the effects of only one independent variable.
  46. 46. Completely Randomized Designs Average minutes shopper spends in store Control: no music Experimental treatment: slow music Experimental treatment: fast music 16 18 12
  47. 47. Independent Variable A Group A Group B Group C Level 1 Level 2 Level 3
  48. 48. Completely Randomized Design With a pretest posttest Group A R O1 X1 O2 Group A R O3 X2 O4 Group A R O5 X3 O6
  49. 49. With a posttest Group A R X1 O1 Group B R X2 O2 Group C R X3 O3 Completely Randomized Design
  50. 50. Randomized Block Design • An extension of the completely randomized design in which a single extraneous variable that might affect test units’ response to the treatment has been identified and the effects of this variable are isolated by blocking out its effects.
  51. 51. Independent Variables Control: no music Experimental treatment slow music Experimental treatment: fast music Mornings and afternoons Evening hours Blockingvariable Randomized Block Design
  52. 52. Factorial Design • An experiment that investigates the interaction of two or more variables on a single dependent variable.
  53. 53. Independent Variable 1 No Music cart signs Slow Music Fast MusicNo Music Grocery cart signs IndependentVariable2
  54. 54. Price Red Gold $25 Cell 1 Cell 4 $30 Cell 2 Cell 5 $35 Cell 3 Cell 6 Package Design Factorial Design -- Roller Skates
  55. 55. Effects • Main effect • The influence of a single independent variable on a dependent variable. • Interaction effect • The influence on a dependent variable by combinations of two or more independent variables.
  56. 56. Men Women Ad A Ad B 65 65 70 60 Main Effects of Gender Main Effects of Ad > > 2 x 2 Factorial Design
  57. 57. 100 90 80 70 60 50 40 30 20 10 Ad A Ad B Women Men Believability Interaction Between Gender and Advertising Copy
  58. 58. Level 1 Level 2 Level 1 Level 2 Group A Group DGroup C Group B Independent Variable2 Independent Variable 1
  59. 59. Group A R O1 X11 O2 Group B R O3 X21 O4 Group C R O5 X12 O6 Group D R O7 X22 O8 2 x 2 Factorial with a Pretest Posttest
  60. 60. Group A R X11 O1 Group B R X21 O2 Group C R X12 O3 Group D R X22 O4 2 x 2 Factorial Design with a Posttest Measure
  61. 61. A Test Market Experiment on Pricing Sales in Units (thousands) Regular Price $.99 130 118 87 84 X1=104.75 X=119.58 Reduced Price $.89 145 143 120 131 X2=134.75 Cents-Off Coupon Regular Price 153 129 96 99 X1=119.25 Test Market A, B, or C Test Market D, E, or F Test Market G, H, or I Test Market J, K, or L Mean Grand Mean
  62. 62. Latin Square Design • A balanced, two-way classification scheme that attempts to control or block out the effect of two or more extraneous factors by restricting randomization with respect to the row and column effects.
  63. 63. 1 2 3 1 A B C 2 B C A 3 C A B Order of Usage SUBJECT
  64. 64. TEST MARKETING Controlled experimentationControlled experimentation Not just tryingNot just trying somethingsomething outout But scientificBut scientific testingtesting
  65. 65. Controlled experimentationControlled experimentation Not just tryingNot just trying somethingsomething outout But scientificBut scientific testingtesting Test Marketing
  66. 66. Test Marketing • An experimental procedure that provides an opportunity to test a new product or a new marketing plan under realistic market conditions to measure sales or profit potential.
  67. 67. ESTIMATEESTIMATE OUTCOMESOUTCOMES IDENTIFY ANDIDENTIFY AND CORRECTCORRECT WEAKNESSESWEAKNESSES IN PLANSIN PLANS Functions of Test Marketing
  68. 68. A Lengthy and Costly Procedure $$$$$$$$$$ Loss ofLoss of SecrecySecrecy When notWhen not to Test?to Test? How LongHow Long Should aShould a Test Last?Test Last?
  69. 69. Popular Test Markets • Pittsfield, Massachusetts • Charlotte, North Carolina • Columbus, Ohio • Little Rock, Arkansas • Evansville, Indiana • Cedar Rapids, Iowa • Eau Claire,Wisconsin • Wichita, Kansas • Tulsa, Oklahoma • Omaha, Nebraska • Grand Junction. Colorado • Wichita Falls, Texas • Odessa-Midland, Texas
  70. 70. Selecting a Test Market • Population size • Demographic composition • Lifestyle considerations • Competitive situation • Media • Self-contained trading area • Overused markets - secrecy
  71. 71. Control Method of Test Marketing • Small city • Low chance of being detected • Distribution is forced (guaranteed)
  72. 72. The Advantages of Using the Control Method of Test Marketing • Reduced costs • Shorter time period needed for reading test market results • Increased secrecy from competitors • No distraction of company salespeople from regular product lines
  73. 73. Some Problems Estimating Sales Volume • Over-attention • Unrealistic store conditions • Reading competitive environment incorrectly • Incorrect volume forecasts – Adjusted data – Penetration and repeat purchase rate • Time lapse
  74. 74. High Tech Test Markets ElectricElectric TestTest MarketsMarkets SimulatedSimulated TestTest MarketsMarkets Virtual-realityVirtual-reality SimulatedSimulated Test MarketsTest Markets

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