Showing Error Bars in Charts
You can show error bars around data points in all 2D charts, except for pie charts. Error
bars indicate how much error there might be in a particular data point.
To show error bars for the data points in a selected series:
In the Chart inspector, click Series, and then click Advanced at the bottom of the
Inspector window. Then click Error Bars.
For scatter plots, you can have error bars for both data series. Set them separately by
following the instructions for both the axes.
From the pop-up menu, choose the way you want the error bars to be displayed:
Positive and Negative: Displays full error bars, both above and below each data point.
Positive Only: Displays only the part of each error bar that falls above its data point.
Negative Only: Displays only the part of each error bar that falls below its data point.
From the second pop-up menu, choose the kind of error bar you want to display:
Fixed Value: Displays an error bar of the same absolute value for every data point.
Specify a value in the adjacent field.
Percentage: Displays error bars based on a fixed percentage of each data point value.
Specify a percentage in the adjacent field.
Standard Deviation: Displays error bars based on the standard deviation of your data
set. Specify the number of standard deviations in the adjacent field.
Standard Error: Displays standard error bars.
Custom: Lets you set error bars based on your own criteria. In the Positive field, specify
how far above the data points you want the error bars to extend; in the Negative field,
specify how far below the data points you want the error bars to extend.
In the field adjacent to the second pop-up menu, specify the error bar range.
Select an error bar, click the Graphic inspector button, and optionally change the error
bar line ends using the Stroke pop-up menu.