Showing Trendiness in Charts
Trendlines are lines calculated and drawn to fit your data, according to the type of
equation you prefer. You can display trendlines for most 2D charts, except stacked bar,
column, area, and pie charts.
To show a trendline for the data points in a selected series:
1
Select one or more series for which you want to show a trendline, and then click the
Inspector button in the toolbar.
2
Click Chart in the Inspector window, and then click Series.
3
Click Advanced at the bottom of the Series pane. Then click Trendline.
4
From the pop-up menu, choose the type of equation you want to use to calculate
the trendline:
Linear: Produces a best-fit straight line, most useful for simple, linear data series.
Logarithmic: Produces a best-fit curved line, most useful when values increase or
decrease quickly, then level out.
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Chapter 7
Creating Charts from Data
Chapter 7
Creating Charts from Data
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Polynomial: Produces a curved line that has hills and valleys to show where values
rise or fall. Specify the order of polynomial you want to use in the Order field; order 4
produces as many as 3 hills or valleys.
Power: Produces a curved line for use when you want to compare measurements
that increase at a specific rate. Power can’t be used with data that contains zero or
negative values.
Exponential: Produces a curved line for use when values rise or fall at increasingly
higher rates. Exponential can’t be used with data that contains zero or negative values.
Moving Average: Produces a trendline using the number of data points you specify in
the Period field, averages them, and uses the average value as a trendline point.
5
To see the equation that describes a trendline, select the line, and then select Show
Equation. You can drag this equation to wherever you want it to appear on the sheet.
6
To see the R-squared value that was used to calculate a trendline, select the line, and
then select Show R^2 Value. You can drag this number to wherever you want it to
appear on the sheet.
7
To display a label for a trendline, select the trendline and then select Label. Type a label
in the adjacent field.
8
To change the line color or thickness of a trendline, select the trendline, and
then click the Graphic button in the Inspector window. Make adjustments using the
Stroke controls.