Experiment Settings
LEARNING OUTCOMES
Basic characteristics of experiments
2. Experimental effects
3. Issues in experimental design
1.



4.
5.
6.
7.
9–2
8.
Manipulation of IV
Measurement of DV
Selection of test units
Different types of experiment designs
Manipulation check
Internal validity of experiments
Test-marketing
Design a basic and factorial experiment
Research Questions
 Does jogging make you feel better?
 Does point-of-purchase advertising influence sales?
 Is the anti-drug campaign successful in decreasing the
drug usage?
 What is the effect of color and lighting on shopper
patronage?
Experiments
Experimental Conditions
in Color and Lighting Experiment
EXHIBIT 9.1
9–4
The Characteristics of Experiments
 Subjects (a.k.a. Participants)
 Human respondents who provide measures based on experimental
manipulation.
 Experimental Condition
 One of the possible levels of an experimental (independent) variable
manipulation.
 Independent Variable (IV) & Dependent Variable (DV)
9–5
Consumer Average Patronage Scores in
Each Condition
EXHIBIT 9.2
Main Effect of Color on Consumer Patronage:
Blue color attracted consumers more than did orange color.
9–6
EXHIBIT 9.3 Experimental
Graph Showing
Interaction Effect
9–7
EXHIBIT 9.3 Experimental
Graph Showing
Interaction Effect
The effect of color on consumer patronage is stronger when
the lighting is bright than when the lighting is soft.
9–8
Experimental Effects
 Main effect: The experimental difference in dependent
variable means between the different levels of any single
experimental variable.
 The effect of a single IV on a DV, regardless of the other IV.
 Interaction effect: Differences in dependent variable
means due to a specific combination of independent
variable.
 The effect of one IV on DV depends on the level of the other IV.
9–9
LEARNING OUTCOMES
Basic characteristics of experiments
2. Experimental effects
3. Issues in experimental design
1.



4.
5.
6.
7.
9–10
8.
Manipulation of IV
Measurement of DV
Selection of test units
Different types of experiment designs
Manipulation check
Internal validity of experiments
Test-marketing
Design a basic and factorial experiment
All of the following are experimental design issues EXCEPT:
a. selection and assignment of subjects to treatments
b. control over extraneous variables
c. manipulation of the independent variable
d. manipulation of the dependent variable
d. manipulation of dependent variable
Basic Issues in Experimental Design
 Manipulation of the Independent Variable
 Experimental treatment: the way an experimental variable is
manipulated.
 Categorical variables: class or quality (e.g., color)
 Continuous variables: quantity (level) (e.g., price)
Experimental
Group
9–12
Experimental
Treatment
Control Group
Experimental Design (cont’d)
 Manipulation of the Independent Variable
 Several experimental treatment levels (different values of the
independent) may be used.
 More than one independent variable may be examined.
 Cell: a specific treatment combination associated with an
experimental group.
 How to compute # of cells in an experiment:
K = (T1)(T2)..(Tm)
9–13
Experimental Design (cont’d)
 Selection and Measurement of the Dependent Variable
 Selecting dependent variables that are relevant and truly
represent an outcome of interest is crucial.
 Will outcomes of the dependent variable (information or insights
gained) assist managers in decision making?
Sales
Ad Attitude
Purchase Intention
9–14
Brand Attitude
Recall
Experimental Design (cont’d)
 Selection and Assignment of Test Units
 Test units: the subjects or entities whose responses to treatment
are measured or observed.
 Randomization
 Random assignment of subject and treatments to groups
 Device for equally distributing the effects of extraneous variables to all
conditions.
 Repeated measures
 Experiments in which individual subject is exposed to more than one level
of an experimental treatment.
9–15
Methods of Random Selection
 Tossing a perfect coin
 Using computer programs that provide random selection
 Use random number table
16
Demand Characteristics and
Experimental Validity
 Demand Characteristic
 An experimental design element or procedure that unintentionally
provides subjects with hints about the research hypothesis.
 Demand Effect
 Occurs when demand characteristics actually affect the dependent
variable.
9–17
Reducing Demand Characteristics
 Experimental disguise
 Placebo – an experimental deception involving a false
treatment.
 Placebo effect – the corresponding effect in a dependent
variable that is due to the psychological impact that goes
along with knowledge that a treatment has been
administered.
 Isolate experimental subjects
 Use a “blind” experimental administrator
 Administer only one experimental condition per subject
9–18
Establishing Control
 Constancy of Conditions
 Subjects in all experimental groups are exposed to identical
conditions except for the differing experimental treatments.
 Counterbalancing
 Attempts to eliminate the confounding effects of order of
presentation by varying the order of presentation (exposure) of
treatments to subject groups.
9–19
LEARNING OUTCOMES
Basic characteristics of experiments
2. Experimental effects
3. Issues in experimental design
1.



4.
5.
6.
7.
9–20
8.
Manipulation of IV
Measurement of DV
Selection of test units
Different types of experiment designs
Manipulation check
Internal validity of experiments
Test-marketing
Design a basic and factorial experiment
Basic versus Factorial Experimental
Designs
 Basic Experimental Designs
 A single independent variable and a single dependent
variable.
 Factorial Experimental Designs
 Allows for an investigation of the interaction of two or
more independent variables.
9–21
Laboratory and Field Experiments
 Laboratory Experiment
 A situation in which the researcher has more complete
control over the research setting and extraneous
variables.
 Field Experiments
 Research projects involving experimental
manipulations that are implemented in a natural
environment.
9–22
EXHIBIT 9.5
The Artificiality of Laboratory versus Field Experiments
•High control
•Strong causal relationship
9–23
•Low control
•Weak causal relationship
Withinand
BetweenSubjects
Designs
9–24
Advantages of Between-Subjects
Designs
 Within-Subjects Design
 Involves repeated measures because with each treatment the
same subject is measured.
 Between-Subjects Design
 Each subject receives only one treatment combination.
 Usually advantageous although they are usually more costly.
 Validity is usually higher.
9–25
Exercise: Questions
Suppose you wanted to test the effect of three different email requests
inviting people to participate in a survey posted on the Internet. One
simply contained a hyperlink with no explanation, the other said if
someone participated $10 would be donated to charity, and the other
said if someone participated he or she would have a chance to win
$100.
1. To design an experimental study, how many
experimental conditions will there be?
2. If 15 participants are needed for each experimental
condition, how many participants in total are needed for a
between-subjects design? Within-subjects design?
3. How many times does each participant need to be
measured for the dependent variable in a betweensubjects design? Within-subjects design?
26
Answers
1. 3 experimental conditions.
2. 45 people needed for between-subjects
design; 15 needed for within-subjects
design.
3. 3 times in within-subjects design; 1 time in
between-subjects design.
9–27
Internal Validity
 Internal 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?
 6 threats (factors) to internal validity (SKIP pp. 230-232)
 Manipulation Checks
 A validity test of an experimental manipulation to make sure
that the manipulation does produce differences in the
independent variable.
9–28
Uses of Test-Marketing
Forecasting New
Product Success
Testing the
Marketing Mix
TestMarketing
Identifying Product
Weaknesses
9–29
EXHIBIT 3.2 Testing
3–30
for Causes with an Experiment
Advantages and Disadvantages of
Test-Marketing
 Advantages
 Real-world setting
 Easily communicated results
 Disadvantages
 Cost
 Time
 Loss of secrecy
9–31