Information Technology Reference
In-Depth Information
This value is
obtained as follows:
zero month mean
minus two month
mean = 412.8571 -
474.2857 = - 61.4286.
Multiple Comparisons
satscore
Tukev HSD
95% Confidence Interval
Mean
Difference (I-J)
(I) months of
study
(J) months of
study
Sig.
Std. Error
Lower Bound
Upper Bound
zero months
two months
four months
six months
eight months
zero months
four months
six months
eight months
zero months
two months
six months
eight months
zero months
two months
four months
eight months
zero months
two months
four months
eight months
−
61.42857
′
−
140.00000
′
−
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
19.46216
.028
.000
.000
.000
.028
.003
.000
.000
.000
.003
.028
.009
.000
.000
.028
.992
.000
.000
.009
.992
−
117.8807
−
196.4521
−
−
4.9765
−
83.5479
The mean difference
of - 61.4286 is
significant based on
an alpha of .05.
201.42857
′
257.8807
−
266.4521
4.9765
−
144.9765
−
153.5479
117.8807
−
210.00000
′
−
61.42857
′
−
78.57143
′
−
two months
.
135.0235
22.1193
−
−
140.00000
′
−
148.57143
′
−
140.00000
′
−
78.57143
′
−
−
196.4521
−
205.0235
83.5473
22.1193
−
117.8807
−
126.4521
144.9765
83.5479
4.9765
−
65.0235
153.5479
92.1193
13.5479
−
47.8807
−
83.5479
92.1193
190.4521
135.0235
−
4.9765
−
13.5479
257.8807
196.4521
117.8807
47.8807
266.4521
205.0235
126.4521
65.0235
four months
61.42857
′
−
70.00000
′
−
201.42857
′
−
In this row, the two
month study group is
compared to each of
the other groups.
six months
140.00000
′
−
61.42857
′
−
8.57143
′
−
210.00000
′
−
eight months
148.57143
′
−
70.00000
′
−
8.57143
′
*. The mean difference is significant at the 0.05 level.
Figure 7.6
Tukey HSD multiple comparisons.
SPSS uses in a variety of its ANOVA procedures to present the detailed
findings of pairwise comparisons.
Each of the major rows of the display focuses on one of the groups.
The lines within the major rows present the pairwise comparisons. In
the first line of the first major row, for example, the zero month study
group is compared to the two months study group. The mean difference
is
61.4286. This value was obtained by the following subtraction (the
last decimal place may not give the exact results since the printed out-
put gives fewer decimal places than the application uses in its computa-
tions):
−
zero month mean minus two month mean
412.8571
−
=
474.2857
=−
61.4286.
Specifically, each of the comparison groups (the ones named in the second
column) is subtracted from the focus group (the group in the first column).
Note that when the two month study group is the focus group and the zero
month study group is the comparison group (the first line of the second
major row), the difference is 61.4286 because of the different order of the
subtraction. Thus, there is a certain amount of repeated information in the
table, which is why it is much larger than the display of the homogeneous
subsets. If you continue to read the line where we have the mean difference
of
4286 between the zero month and the two months study groups,
you will reach the column labeled
Sig.
This is the probability of such a
−
61
.
