Microsoft Office Tutorials and References
In Depth Information
Considerations When Using Regression Analysis
Figure 14.12.
Figure 14.12. These two data sets can be accurately predicted using regres-
These two data sets can be accurately predicted using regres-
sion.
sion.
The chart on the right shows an exponential growth curve. In this chart, the
dotted line shows the regression line plotted using LOGEST. Again, although
the dotted line does not correlate exactly with the actual data points, it is
fairly close.
Here is the problem: Regression always finds a line to fit your data set.
In Figure 14.13 , no apparent correlation exists between sales and time. Each
year, the sales fluctuate wildly up or down. If you asked Excel to use re-
gression, it would gladly predict the dotted line shown in the graph. The prob-
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