Wednesday, March 8, 2017

Add, change, or remove error bars in a chart

Add, change, or remove error bars in a chart

Error bars in charts you create can help you see margins of error and standard deviations at a glance. They can be shown on all data points or data markers in a data series as a standard error amount, a percentage, or a standard deviation. You can set your own values to display the exact error amounts you want. For example, you can show a 10 percent positive and negative error amount in the results of a scientific experiment like this:

Line chart with 10 percent error bars

You can use error bars in 2-D area, bar, column, line, xy (scatter), and bubble charts. In scatter and bubble charts, you can show error bars for x and y values.

Click the following headings for more information.

  1. Click anywhere in the chart.

  2. Click the Chart Elements button Chart Elements button next to the chart, and then check the Error Bars box. (Clear the box to remove error bars.)

  3. To change the error amount shown, click the arrow next to Error Bars, and then pick an option.

    Error Bar options

    • Pick a predefined error bar option like Standard Error, Percentage or Standard Deviation.

    • Pick More Options to set your own error bar amounts, and then under Vertical Error Bar or Horizontal Error Bar, choose the options you want. This is also where you can change the direction, end style of the error bars, or create custom error bars.

      Format Error Bars pane

Note: The direction of the error bars depends on the type of chart you're using. Scatter charts can show both horizontal and vertical error bars. You can remove either of these error bars by selecting them, and then pressing Delete.

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People often ask how Excel calculates error amounts. Excel uses the following equations to calculate the Standard Error and Standard Deviation amounts that are shown on the chart.

This option

Uses this equation

Standard Error

Equation

Where:

s = series number

i = point number in series s

m = number of series for point y in chart

n = number of points in each series

yis = data value of series s and the ith point

ny = total number of data values in all series

Standard Deviation

Equation

Where:

s = series number

i = point number in series s

m = number of series for point y in chart

n = number of points in each series

yis = data value of series s and the ith point

ny = total number of data values in all series

M = arithmetic mean

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Click the following headings for more information.

In Excel, you can display error bars that use a standard error amount, a percentage of the value (5%), or a standard deviation.

Standard Error and Standard Deviation use the following equations to calculate the error amounts that are shown on the chart.

This option

Uses this equation

Where

Standard Error

Equation

s = series number

i = point number in series s

m = number of series for point y in chart

n = number of points in each series

yis = data value of series s and the ith point

ny = total number of data values in all series

Standard Deviation

Equation

s = series number

i = point number in series s

m = number of series for point y in chart

n = number of points in each series

yis = data value of series s and the ith point

ny = total number of data values in all series

M = arithmetic mean

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  1. On 2-D area, bar, column, line, xy (scatter), or bubble chart, do one of the following:

    • To add error bars to all data series in the chart, click the chart area.

    • To add error bars to a selected data point or data series, click the data point or data series that you want, or do the following to select it from a list of chart elements:

      1. Click anywhere in the chart.

        This displays the Chart Tools, adding the Design, Layout, and Format tabs.

      2. On the Format tab, in the Current Selection group, click the arrow next to the Chart Elements box, and then click the chart element that you want.

        excel ribbon image

  2. On the Layout tab, in the Analysis group, click Error Bars.

    Excel Ribbon Image

  3. Do one of the following:

    1. Click a predefined error bar option, such as Error Bars with Standard Error, Error Bars with Percentage, or Error Bars with Standard Deviation.

    2. Click More Error Bar Options, and then under Vertical Error Bars or Horizontal Error Bars, click the display and error amount options that you want to use.

      Note: The direction of the error bars depends on the chart type of your chart. For scatter charts, both horizontal and vertical error bars are displayed by default. You can remove either of these error bars by selecting them, and then pressing DELETE.

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  1. On a 2-D area, bar, column, line, xy (scatter), or bubble chart, click the error bars, the data point, or the data series that has the error bars that you want to change, or do the following to select them from a list of chart elements:

    1. Click anywhere in the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    2. On the Format tab, in the Current Selection group, click the arrow next to the Chart Elements box, and then click the chart element that you want.

      excel ribbon image

  2. On the Layout tab, in the Analysis group, click Error Bars, and then click More Error Bar Options.

    Excel Ribbon Image

  3. Under Display, click the error bar direction and end style that you want to use.

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  1. On a 2-D area, bar, column, line, xy (scatter), or bubble chart, click the error bars, the data point, or the data series that has the error bars that you want to change, or do the following to select them from a list of chart elements:

    1. Click anywhere in the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    2. On the Format tab, in the Current Selection group, click the arrow next to the Chart Elements box, and then click the chart element that you want.

      excel ribbon image

  2. On the Layout tab, in the Analysis group, click Error Bars, and then click More Error Bar Options.

    Excel Ribbon Image

  3. Under Error Amount, do one or more of the following:

    1. To use a different method to determine the error amount, click the method that you want to use, and then specify the error amount.

    2. To use custom values to determine the error amount, click Custom, and then do the following:

      1. Click Specify Value.

      2. In the Positive Error Value and Negative Error Value boxes, specify the worksheet range that you want to use as error amount values, or type the values that you want to use, separated by commas. For example, type 0.4, 0.3, 0.8.

        Tip: To specify the worksheet range, you can click the Collapse Dialog button Collapse button , and then select the data that you want to use in the worksheet. Click the Collapse Dialog button again to return to the dialog box.

        Note: In Microsoft Office Word 2007 or Microsoft Office PowerPoint 2007, the Custom Error Bars dialog box may not show the Collapse Dialog button, and you can only type the error amount values that you want to use.

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  1. On a 2-D area, bar, column, line, xy (scatter), or bubble chart, click the error bars, the data point, or the data series that has the error bars that you want to remove, or do the following to select them from a list of chart elements:

    1. Click anywhere in the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    2. On the Format tab, in the Current Selection group, click the arrow next to the Chart Elements box, and then click the chart element that you want.

      excel ribbon image

  2. Do one of the following:

    1. On the Layout tab, in the Analysis group, click Error Bars, and then click None.

      Excel Ribbon Image

    2. Press DELETE.

Tip: You can remove error bars immediately after you add them to the chart by clicking Undo on the Quick Access Toolbar or by pressing CTRL+Z.

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