Microsoft Office Tutorials and References
In Depth Information
Chapter 5: Working with Trendlines and Error Bars
Chapter 5
Working with Trendlines
and Error Bars
IN THIS CHAPTER
Adding a trendline to a data series
Forecasting and predicting with trendlines
Using error bars
Adding other types of series enhancements
T HIS CHAPTER DISCUSSES CHARTING features that can make certain charts more
meaningful: trendlines and error bars. A trendline is an additional line added to a chart
that depicts general trends in your data. In some cases, you can forecast future data
with a trendline. Error bars, used primarily in scientific applications, indicate “plus
or minus” information that reflects uncertainty in the data. In addition, some chart
series can display other enhancements such as series lines, drop lines, high-low
lines, and up/down bars. These topics are all covered in this chapter.
Working with Trendlines
The best way to become acquainted with trendlines is to see one. Figure 5-1 shows
an area chart that displays monthly income for 65 time periods. A trendline has
been added to the chart. Although this data fluctuates quite a bit, the trendline
indicates that income, in general, has been increasing — something that might not
be readily apparent without the assistance of the trendline.
When a trendline is added to a chart, Excel draws the line such that it minimizes
the differences between each data point and the corresponding value on the
trendline. In other words, the trendline is the “best fit” line for the data series.
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