Review
1. Hypothesis testing
– Ho: and H1:
– p-value vs α ⇒ if p-value < α : reject Ho
if p-value > α : Not reject Ho
2. Frequency
– Description of one variable
3. Cross
- tabulation (nominal variables)
– Description of more than one variable
Data Analysis III
T-test and ANOVA
– Ho: variables in the table are NOT associated.
– Magnitude of association : χ2
Objective
Marketing Research Process
1. Problem Definition
2. Development of an Approach to the Problem
3. Research Design Formulation
4. Data Collection
Analysis
Analysis of
of “Difference”
“Difference”
1. T-test
– Comparison between two groups
2. ANOVA(Analysis of Variance)
5. Data Analysis
– Comparison among more than 2 groups
6. Report Preparation and Presentation
1. T-test
• Promotion:
Yes
No
• Introductory Example (Retail Store)
Two Cases:
Offering promotional deal,
Offering regular price
Managerial Interest: Sales
Q: Are sales different between the two cases, when
we offer promotion and when we do not?
Significant
Significant difference
difference ??
• Sales Sales_1 = or ≠ Sales_2
H
Hoo:: Sales_1
Sales_1 == Sales_2
Sales_2
H
Sales_1
H11:: Sales_1
≠≠
Sales_2
Sales_2
1
Structure of T-test
• Variables: 2 variables
Structure of T-test
• Hypothesis
– Variable 1(independent variable or grouping
variable): Nominal scale / takes only two
values
– Variable 2(dependent variable): Interval or
Ratio Scale
• Testing the difference in variable 2
between the two groups categorized by
variable 1
Appropriate Marketing Examples
• Ex1. Sales person training program
– Program 1 and 2
– Is the average performance of those who were
trained by program 1 different from that of
those who were trained by program2?
– Ho: There’s no significant difference in
dependent variable between different groups.
– H1: There’s significant difference in
dependent variable between different groups.
• Decision rule
– reject Ho if α > p-value
– Not reject Ho if α < p-value
Q1. How do you feel visiting Stonestown Mall
after dark?
Q2. Your gender is: (1) Male
(2) Female
1
2
3
4
5
• Ex2. Stonestown Mall
– Are the students’ perceptions on safety in
Stonestown Mall different between female
and male?
Procedure of T-test
Identify
Identifyvariables:
variables:
1.
1.grouping
groupingvariable
variable?? The
Thevariable
variableshould
shouldhave
haveonly
onlytwo
twovalues.
values.
(Nominal
(Nominalscale)
scale)
2.
2.dependent
dependentvariable
variable??Should
Shouldbe
bemeasured
measuredby
bymetric
metricscales.
scales.
State
StateHypotheses:
Hypotheses:
1.
nodifference
differencebetween
betweengroups
groups
1.HHoo::no
2.
2.HH1::There’s
There’sdifference
differencebetween
betweengroups
groups
1
1.
1.Get
Getthe
thecomputer
computeroutput
output
2.
2.Compare
Comparethe
thep-value
p-valuewith
withα
α
very safe
very unsafe
T-test Using SPSS
Go to the other handout
IfIfp-value
p-value<<α
α
Reject
RejectHo
Ho
– How to do t-test in SPSS
– How to interpret the results (computer output)
IfIfp-value
p-value>>α
α
Do
Donot
notreject
rejectHo
Ho
2