Information Technology Reference
In-Depth Information
Levene's Test of Equality of Error Variances
a
The Levene test yielded an
F
ratio that was not statistically
significant. Thus, our data
have met the assumption of
homogeneity of variance.
Dependent Variable: satis public schools
F
df1
df2
Sig.
.731
11
48
.704
Tests the null hypothesis that the error variance of the
dependent variable is equal across groups.
Design: Intercept+kidshome+voter+politics+kidshome
* voter+kidshome * politics+voter * politics+kidshom
voter * politics
a.
Figure 9.9
The results of the Levene test.
The summary table for the omnibus analysis is shown in Figure 9.10,
and duplicates the information we presented in Table 9.1. As we already
know, all of the effects except for the main effect of
voter
are statistically
significant. The
Corrected Model
combines all of our effects (the main
effects and interactions); the
RSquared
associated with it (shown in the
footnote to the table) is a complete eta squared for these combined effects,
and so is not useful for our purposes (we compute separate eta squared
values for each of the statistically significant effects).
9.8 PERFORMING THE POST-ANOVA ANALYSES IN SPSS
The omnibus analysis indicated that most of the effects were statistically
significant.Ourfocuswillbeonthemaineffectof
politics
(because it has
more than two levels) and the three-way interaction.
These are the
probabilities of the
F
ratio occurring by chance
alone for the main
effects and interactions.
Tests of Between-Subjects Effects
Dependent Variable: satis publics schools
Type III Sum
of Squares
Source
Corrected Model
Intercept
KIDSHOME
VOTER
POLITICS
KIDSHOME * VOTER
KIDSHOME * POLITICS
VOTER * POLITICS
KIDSHOME * VOTER *
POLITICS
Error
Total
Corrected Total
Sig.
df
11
1
Mean Square
F
a
5360.000
40560.000
326.667
106.667
1672.500
326.667
1060.833
490.833
487.273
13.856
1153.365
9.289
.000
.000
.004
40560.000
326.667
1
1
2
1
2
2
106.667
836.250
3.033
23.780
.088
.000
We focus on the triple
interaction (A×B×C)
because it is statistically
significant.
326.667
530.417
245.417
9.289
15.083
6.979
.004
.000
.002
1375.833
2
42
60
59
687.917
19.562
.000
1688.000
35.167
47608.000
7048.000
a. R Squared
=
.760 (Adjusted R Squared
=
.705)
Figure 9.10
The summary table produced by SPSS.
