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Exhibit 3.8 Enabling the analysis ToolPak add-in
With time series data, we are particularly interested in how the data varies over
time and in identifying patterns that occur systematically over time. A graph of the
data, as in Exhibit 3.9, is our first step in the analysis. As the British Anthropologist,
John Lubbock, wrote: What we see depends mainly on what we look for, and herein
we see the power of Excel’s charting capabilities. We can carefully scrutinize— look
for —patterns of behavior before we commit to more technical analysis. Behavior
like seasonality, co-relationship of one series to another, or one series display-
ing leading or lagging time behavior with respect to another are relatively easy to
observe.
Now, let us investigate the graphical representation of data in Exhibit 3.9. Note
that if many series are displayed simultaneously, the resulting graph can be very
confusing. Thus, we display each series separately. The following are some of the
interesting findings for our sales data:
1. It appears that all of the product sales have some cyclicality except for D; that
is, the data tends to repeat patterns of behavior over some relatively fixed time
length (a cycle). Product D may have a very slight cyclical behavior, but is it not
evident by graphical observation.
2. It appears that A and E behave relatively similarly for the first three years,
although their cyclicality is out of phase by a single quarter. Cyclicality that
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