Statistics for the Behavioral Sciences by Frederick J. Gravetter, Larry B. Wallnau ISBN 10: 1305504917 ISBN 13: 9781305504912

APPENDIX C | Solutions for Odd-Numbered Problems in the Text 677
7. a. The scores in treatment 1 are consistently higher
than the scores in treatment 2. There is a main
effect for treatment.
b. The overall mean is around M = 15 for all three
age groups. There is no main effect for age.
c. The two lines are not parallel. Instead, the difference
between the treatments increases as the
participants get older. Yes, there is an interaction.
9. a. df = 1, 54
11. a. 3
13. a.
b. df = 2, 54
c. df = 2, 54
b. 4
c. 6, 108
Source SS df MS
Between Treatments 400 5
A 120 1 120 F(1, 24) = 15.00
B 260 2 130 F(2, 24) = 16.25
A × B 20 2 10 F(2, 24) = 1.25
Within Treatments 192 24 8
Total 592 29
15. a.
The F-ratio for factor A has df = 1, 24 and the critical
value is F = 4.26. Factor B and the interaction
have df = 2, 24 and the critical value is 3.40. The
main effect is significant for both factors but not for
the interaction.
b. For level B1 F = 10 8 = 1.25, for B2 F = 40 8 =
5.00, and for B3 F = 90 8 = 11.25. For all tests,
df = 1, 24 and the critical value is 4.26. There
are significant differences at levels B2 and B3 but
not at B1.
Source SS df MS
Between Treatments 40 3
Type of Program 20 1 20 F(1, 16) = 8.89
Amount of Time 0 1 0 F(1, 16) = 0
A × B 20 1 20 F(1, 16) = 8.89
Within Treatments 36 16 2.25
Total 76 19
With df = 1, 16, the critical value for all three F-ratios
is 8.53. The main effect for the type of program and
the interaction are significant. The main effect for
amount of TV watching is not significant.
b. For the type program factor and the interaction,
eta squared is 20
56 = 0.357. For the time factor, eta
squared is 0.
17.
c. For educational TV, increased watching time
results in significantly higher performance, but for
noneducational TV, increased watching results in
lower performance.
Source SS df MS
Between Treatments 74 7
A 20 1 20 F(1, 32) = 10
B 36 3 12 F(3, 32) = 6
A × B 18 3 6 F(3, 32) = 3
Within Treatments 65 32 2
Total 138 39
19.
Source SS df MS
Between Treatments 52 3
A 16 1 16 F(1, 56) = 8.00
B 24 1 24 F(3, 56) = 12.00
A × B 12 1 12 F(3, 56) = 6.00
Within Treatments 112 56 2
Total 164 59
21. a.
Source SS df MS
Between Treatments 360 5
Gender 72 1 72 F(1, 12) = 9.00
Treatments 252 2 126 F(2, 12) = 15.75
Gender × Treat. 36 2 18 F(2, 12) = 2.25
Within Treatments 96 12 8
Total 456 17
With df = 1, 12, the critical value for the gender main
effect is 4.75. The main effect for gender is significant.
With df = 2, 12, the critical value for the treatment
main effect and the interaction is 3.88. The main effect
for treatments is significant but the interaction is not.
b. For treatment I, F = 0; for treatment II,
F = 54 8 = 6.75; and for treatment III,
F = 54 8 = 6.75. With df = 1, 12, the critical value
for all three tests is 4.75. The results indicate a
significant difference between males and females
in treatments II and III, but not in treatment I.
23. a. The means for the six groups are as follows:
Middle School High School College
Non-User 4.00 4.00 4.00
User 3.00 2.00 1.00