10/19/2015Marketing Research2 You have more than two groups and a mean (average) for each ◦...
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Transcript of 10/19/2015Marketing Research2 You have more than two groups and a mean (average) for each ◦...
04/20/23Marketing Research 2
You have more than two groups and a mean (average) for each
◦ e.g., young = 4.0,
◦ middle aged = 5.0,
◦ older = 4.5
How do you determine the strength of the covariation?
04/20/23Marketing Research 3
◦ Decomposes “variance” into:
treatment effects
other factors
unexplained factors
◦ Compares data to group means
Subtracts each data point from group mean
Squares it
Keeps a running total of “Sum of Squares”
04/20/23Marketing Research 4
◦ The Sums of Squares are then:
Divided by the number of groups
(To get an estimate “per group”)
“Mean Squares”
MSSr = SSr / df
(variance per group)
MSSr / MSSu = F
Total variance “explainable”
◦ F compared to F crit [dfn, dfd]
◦ if F > F crit, difference in population
04/20/23Marketing Research 5
◦One way ANOVA investigates:
◦Main effects
factor has an across-the-board effect
e.g., age
or involvement
04/20/23Marketing Research 6
Study of movie profits◦ Dependent variable:
Gross revenue in dollars [continuous]
◦ Independent variables:
Sex [categorical]
Violence
◦ Examine predictors of profitability:
Sex, violence, interaction (sex * violence)
04/20/23Marketing Research 7
2
3
4
5
Low High
No sex
Sex
VIOLENCE LEVEL
04/20/23Marketing Research 8
2
3
4
5
Low High
No sex
Sex
VIOLENCE LEVEL
04/20/23Marketing Research 9
◦ A TWO-WAY ANOVA investigates:
◦ INTERACTIONS
effect of one factor depends on another factor
e.g., larger advertising effects for those with no
experience
importance of price depends on income level and
involvement with the product
04/20/23Marketing Research 10
2
3
4
5
Low High
No sex
Sex
VIOLENCE LEVEL
04/20/23Marketing Research 11
Study of movie profits◦ Dependent variable:
Gross revenue in dollars [continuous]
◦ Independent variables:
Sex [categorical]
Violence
◦ Examine predictors of profitability:
Sex, violence, interaction (sex * violence)
04/20/23Marketing Research 12
Tests of Between-Subjects Effects
Dependent Variable: Total Gross
43744.364a 3 14581.455 5.583 .001
952785.362 1 952785.362 364.803 .000
35467.649 1 35467.649 13.580 .000
10228.369 1 10228.369 3.916 .049
21.589 1 21.589 .008 .928
995088.361 381 2611.780
1991539.265 385
1038832.725 384
SourceCorrected Model
Intercept
SEX
VIOLENCE
SEX * VIOLENCE
Error
Total
Corrected Total
Type III Sumof Squares df Mean Square F Sig.
R Squared = .042 (Adjusted R Squared = .035)a.
04/20/23Marketing Research 13
