Information Technology Reference
In-Depth Information
7
6
5
4
3
2
1
0
Granules
Absent
Granules
Absent
Granules
Absent
Granules
Present
Granules
Present
Granules
Present
White Powder
Sea Green Powder
Baby Blue Powder
Figure 12.2
Bar graph showing the significant three-way interaction.
between the independent and dependent variables; therefore, we select a
bar graph format for our figure. This also gives you the opportunity to
experience a different way to visually depict an interaction from what we
have presented in Chapters 8, 9, and 11.
We have plotted the interaction in Figure 12.2. The most global “break”
is on the basis of powder color; thus, the first four bars represent white
powder, the next four bars represent green powder, and the last four bars
represent blue powder. The next most global break is based on the presence
or absence of granules. That is, within each powder color, the first two
bars represent the presence of granules and the last two bars represent the
absence of granules. Finally, box color is considered; within each granule
condition we show the aqua box and then the orange box. Thus, reading
across the
x
axis from left to right, we can say that box color changes or
increments most rapidly, granules (present or absent) increments next
most rapidly, and powder color increments most slowly. This differential
rate of incrementing will be represented in the data files we will construct
for the analysis in SPSS and SAS.
The simple effects analyses that we will want to perform will be keyed to
this plot and will reveal the fine grain details concerning mean differences.
But certain global outcomes are suggested by a visual inspection of the
graph. First, the green powder did not fare well at all; there is little doubt
that the manufacturer will quickly decide not to pursue that option.
Second, if white powder is used, it appears that it should be packaged in
