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For this data set, the differences between the SPSS and SAS results are
small and, even with the severe Bonferroni correction employed by SAS,
lead us to the same conclusions: (a) the two pretest means do not differ
significantly from each other, (b) the last two posttest means do not differ
from each other, and (c) the other differences are statistically significant.
10.20 COMMUNICATING THE RESULTS
Eight participants suffering from Disease X received Drug ABC in an effort to
reduce the intensity of their symptoms. A baseline one month and one week
prior to treatment yielded a comparable baseline at a symptom intensity of
75.00. Mean intensities measured one week, one month, and one year following
treatment yielded means of 75.00, 55.00, and 35.00. Mauchly's test indicated
that the data violated the assumption of sphericity, W (9)
05.
Based on a Greenhouse-Geisser correction for the violation of sphericity, a
one-way within-subjects ANOVA revealed a significant difference in the pretest
and posttest means, F (1
=
0
.
04, p
<.
2
.
951, 13
.
657)
=
18
.
62, p
<.
05, within-subjects
η
=
.
73. Pairwise comparisons using a Bonferroni correction to maintain an alpha
level of .05 revealed that intensity remained constant from the two pretest
baseline measures, significantly decreased after a week following drug therapy,
and further significantly decreased after one month. Symptom intensity did
not significantly differ from that level at the end of a year.
CHAPTER 10 EXERCISES
10.1 Assume we are interested in the effects of room color on the problem
solving capabilities of fourth grade children. Accordingly, children are asked
to solve ten anagram word puzzles in red, yellow, and white colored rooms.
Assume that the order of the colored rooms was appropriately counterbal-
anced. Children spent ten minutes in each room solving the anagrams. The
dependent variable was the number of correct solutions. The data are as
follows:
Room color
Red
Yellow White
Subject
a 1
a 2
a 3
1
2
4
7
2
2
3
7
3
1
5
5
4
1
5
8
5
3
6
7
a.
Conduct an ANOVA by hand and with SPSS or SAS.
b.
Perform a set of pairwise comparisons by hand and with SPSS or SAS.
 
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