1.
Tests of Between-Subjects Effects
Dependent Variable:TownTrips
Source
Type III Sum of
Squares
Corrected Model
df
Mean Square
F
Sig.
114.307
3
38.102
1.071
.364
3725.860
1
3725.860
104.710
.000
41.251
1
41.251
1.159
.284
Upper
5.250
1
5.250
.148
.702
Gender * Upper
9.121
1
9.121
.256
.614
Error
4483.424
126
35.583
Total
10221.000
130
4597.731
129
Intercept
Gender
Corrected Total
a. R Squared = .007 (Adjusted R Squared = -.008)
The results of the between subjects 2-way ANOVA revealed no overall effect (F (3, 126)
= 1.071, MSE = 35.583, p > .05. This indicates that none of our treatments were different
from one another. Technically, you could just stop there, but I’ll go ahead and present the
remaining tests, just so that you can see what things would look like if you were required
to report the main and interaction effects. The main effect of class year was not
significant (F (1, 126) = 0.148, MSE = 35.583, p > .05), nor was the main effect of gender
(F (1, 126) = 1.159, MSE = 35.583, p > .05). Finally, the interaction effect was not
significant (F (1, 126) = 0.256 MSE = 35.583, p > .05). We did not have enough
evidence to conclude that class year or gender influences the number of trips students take
into town. Nor was there enough evidence to conclude that the effect of gender was
different for upper class and lower class students.
2)
Males
Females
SST
SSM
SSE
=
=
=
=
=
Small
(x) = 15
Mean = 3
(x2) = 47
(x) = 15
Mean = 3
(x2) = 51
Large
(x) = 20
Mean = 4
(x2) = 86
(x) = 5
Mean = 1
(x2) = 7
x2 - G2/N
(47 + 86 + 51 + 7) - (15 + 20 + 15 + 5)2/20
191 - 552/20
191 - 151.25
=
__________________________________________
(T2/n) - G2/N
=
(152/5) + (202/5) + (152/5) + (52/5) - 151.25
=
45 + 80 + 45 + 5 - 151.25
=
175 - 151.25
=
__________________________________________
=
SST - SSM
=
39.75 - 23.75
=
39.75
23.75
16
______________________________________
SSFam
SSGen
SSFxG
=
=
=
=
=
=
=
=
=
[(TA2/n)] - G2/N
=
(15+15)2/10 + (20+5)2/10 - 151.25
=
(302/10) + (252/10) - 151.25
=
90 + 62.5 - 151.25
=
152.2 - 151.25
=
__________________________________________
[(TR2/n)] - G2/N
(15+20)2/10 + (15+5)2/10 - 151.25
(352/10) + (202/10) - 151.25
122.5 + 40 - 151.25
162.5 - 151.25
=
__________________________________________
SSM - (SSA + SSB)
23.75 - (1.25+ 11.25)
23.75- 12.5
=
__________________________________________
1.25
11.25
11.25
Source
Model
Error
Total
Fam. Size
Gender
G*F
Omnibus Test
SS
MS
23.75
7.92
16.00
1.00
39.75
Tests of Individual Factors
1.25
1.25
11.25
11.25
11.25
11.25
df
3
16
19
1
1
1
Fobs
7.92
Fcrit
3.24
1.25
11.25
11.25
4.49
4.49
4.49
The omnibus test was significant because Fobs was greater than Fcrit (from the F-table in
the back of the book): F (3, 16) = 7.92, MSE = 1.00, p < .05. This indicates that at least
one of our factors had a significant effect on desired number of children. The main effect
of family size was not significant because Fobs was less than Fcrit: F (1, 16) = 1.25, MSE
= 1.00, p > .05. This indicates that the people from small families would like to have just
as many kids as people from large families. The main effect of gender was significant: F
(1, 16) = 11.25, MSE = 1.00, p < .05. Males want to have more children than females.
Finally, the interaction effect was also significant: F (1, 16) = 11.25, MSE = 1.00, p < .05.
The interaction was observed because whereas males from larger families want to have
more children than males from smaller families, the opposite was observed for females;
that is, females from smaller families reported wanting to have more children than
females from larger families (see figure below).
5
4
3
Males
Females
2
1
0
Small
Large