Error Bars

Error bars can be displayed for each point on a graph in the horizontal and/or vertical directions. You can choose to have the errors calculated as a relative or absolute error for each point, or you can set a custom error for each point by creating a column that contains a relative or absolute error value for each point. For example, suppose that the sensor you are using has a known error of +/- 0.5. You can choose Error Constant and enter 0.5 as the value for the error. Alternately, suppose you have calculated the error for each point and created a manual entry column that contains those values. As described below, choose Use Column and select the column that contains the values you have calculated.

Define How Error Bars are Calculated

1. Use the Options tab in the Column Options dialog to set up how you want the error calculated for a particular column. To display the Column Options dialog, double-click the column name in the data table, or choose Column Options from the Data menu.
2. Check Error Bar Calculations to turn on error bars for the column. Note: You can turn off the error bars for a column by unchecking Error Bar Calculations.
3. Choose Percentage or Fixed Value.
4. Choose Error Constant or Use Column. If you choose Error Constant, enter the value as a percentage or a fixed value, depending on your choice in the previous step. If you choose Use Column, select the column that contains the error values.
5. Select OK.

Display Error Bars on a Graph

Error bars are automatically turned on in both the horizontal (X) and vertical (Y) directions. Turn off error bars in one or both directions using the Graph Options dialog.

1. To display the Graph Options dialog, double-click the graph or choose Graph Options from the Options menu.
2. Uncheck X Error Bars and/or Y Error Bars and select OK.