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:
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.
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Note:The following procedures apply to Office 2013 and newer versions. Looking for Office 2010 steps?
Add or remove error bars
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Click anywhere in the chart.
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Click the Chart Elements button
next to the chart, and then check the Error Bars box. (Clear the box to remove error bars.) -
To change the error amount shown, click the arrow next to Error Bars, and then pick an option.
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Pick a predefined error bar option like Standard Error, Percentage or Standard Deviation.
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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.
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next to the chart, and then check the Error Bars box. (Clear the box to remove error bars.)
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.
Review equations for calculating error amounts
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 | 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 | 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 |
Add, change, or remove errors bars in a chart in Office 2010
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 | | 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 | | 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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On 2-D area, bar, column, line, xy (scatter), or bubble chart, do one of the following:
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To add error bars to all data series in the chart, click the chart area.
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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:
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Click anywhere in the chart.
This displays the Chart Tools, adding the Design, Layout, and Format tabs.
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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.
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On the Layout tab, in the Analysis group, click Error Bars.
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Do one of the following:
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Click a predefined error bar option, such as Error Bars with Standard Error, Error Bars with Percentage, or Error Bars with Standard Deviation.
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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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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:
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Click anywhere in the chart.
This displays the Chart Tools, adding the Design, Layout, and Format tabs.
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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.
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On the Layout tab, in the Analysis group, click Error Bars, and then click More Error Bar Options.
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Under Display, click the error bar direction and end style that you want to use.
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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:
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Click anywhere in the chart.
This displays the Chart Tools, adding the Design, Layout, and Format tabs.
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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.
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On the Layout tab, in the Analysis group, click Error Bars, and then click More Error Bar Options.
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Under Error Amount, do one or more of the following:
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To use a different method to determine the error amount, click the method that you want to use, and then specify the error amount.
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To use custom values to determine the error amount, click Custom, and then do the following:
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Click Specify Value.
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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
, 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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, 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.-
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:
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Click anywhere in the chart.
This displays the Chart Tools, adding the Design, Layout, and Format tabs.
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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.
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Do one of the following:
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On the Layout tab, in the Analysis group, click Error Bars, and then click None.
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Press DELETE.
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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.
Do any of the following:
Express errors as a percentage, standard deviation, or standard error
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In the chart, select the data series that you want to add error bars to.
For example, in a line chart, click one of the lines in the chart, and all the data marker of that data series become selected.
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On the Chart Design tab, click Add Chart Element.
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Point to Error Bars, and then do one of the following:
| Click | To |
|---|---|
| Standard Error | Apply the standard error, using the following formula: s = series number |
| Percentage | Apply a percentage of the value for each data point in the data series |
| Standard Deviation | Apply a multiple of the standard deviation, using the following formula: s = series number |
Express errors as custom values
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In the chart, select the data series that you want to add error bars to.
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On the Chart Design tab, click Add Chart Element, and then click More Error Bars Options.
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In the Format Error Bars pane, on the Error Bar Options tab, under Error Amount, click Custom, and then click Specify Value.
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Under Error amount, click Custom, and then click Specify Value.
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In the Positive Error Value and Negative Error Value boxes, type the values that you want for each data point, separated by commas (for example, 0.4, 0.3, 0.8), and then click OK.
Note:You can also define error values as a range of cells from the same Excel workbook. To select the range of cells, in the Custom Error Bars dialog box, clear the contents of the Positive Error Value or Negative Error Value box, and then select the range of cells that you want to use.
Add up/down bars
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In the chart, select the data series that you want to add up/down bars to.
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On the Chart Design tab, click Add Chart Element, point to Up/Down Bars, and then click Up/down Bars.
Depending on the chart type, some options may not be available.
See Also
Create a chart
Change the chart type of an existing chart
FAQs
Should I add error bars? ›
Error Bars can be applied to graphs such as Scatterplots, Dot Plots, Bar Charts or Line Graphs, to provide an additional layer of detail on the presented data. Error Bars help to indicate estimated error or uncertainty to give a general sense of how precise a measurement is.
What is the purpose of error bars on a graph? ›Error bars are graphical representations of the variability of data and used on graphs to indicate the error or uncertainty in a reported measurement. They give a general idea of how precise a measurement is, or conversely, how far from the reported value the true (error free) value might be.
What does Error bars mean in a graph? ›Error bars are used to indicate the estimated error in a measurement. In other words, an error bar indicates the uncertainty in a value. In Spotfire, you can use error bars in bar charts, line charts, and scatter plots. Bar charts and line charts can display vertical errors.
Do all bar charts need error bars? ›It makes absolute sense to add error bars to a barchart, such as your graph. However, adding error bars to a histogram is unreasonable, as these 'pointwise' error bars do not improve the 'overall' density approximation which the histogram should illustrate.
Do error bars show reliability? ›Error bars based on confidence intervals (C.I.) also indicate the reliability of a measurement (i.e. part of inferential statistics) — they indicates a range that would capture the population mean CI% of the time (e.g. if you have a 95% C.I., then if you collect 20 samples and calculate their means and C.I.
How do you know what error bars to use? ›Use the standard deviations for the error bars
If the data at each time point are normally distributed, then (1) about 64% of the data have values within the extent of the error bars, and (2) almost all the data lie within three times the extent of the error bars.
For adding individual error bars in excel, you're going to click on your graph, click on the + for chart elements, and select “More Options” from the list of four additional error bars options. A new dialogue will pop up next, and from here, you must choose the series you want to add error bars to and click ok.
How do I make different error bars for each bar in sheets? ›- On your computer, open a spreadsheet in Google Sheets.
- To open the editor panel, double-click the chart.
- Click Customize Series.
- Check the box next to “Error bars.”
- Choose the type and value.
When standard deviation errors bars overlap quite a bit, it's a clue that the difference is not statistically significant. You must actually perform a statistical test to draw a conclusion. When standard deviation errors bars overlap even less, it's a clue that the difference is probably not statistically significant.
Are error bars precision or accuracy? ›One can not just look at the length of the error bars and assume that it means accurate data (to get a bit picky on semantics – also, error bars do not reflect the accuracy of the data, rather it reflects the precision with which you can measure the data).
Why are standard error bars misleading? ›
The standard error only reflects this variability for a particular sample size. If distributions are skewed, or if the variable is only measured on the ordinal scale, then both the standard deviation and the standard error are misleading (albeit not actually incorrect).
Does error measure accuracy? ›Accuracy is for gauging how small/large the error is (a qualitative description), while the Error is the actual representation of accuracy in the same units as the measured parameter (measurand). In other words, the error shows the quantity of accuracy in the unit of measurement used.
How does error affect reliability? ›The amount of random errors is inversely related to the reliability of a measurement instrument. As the number of random errors decreases, reliability rises and vice versa. Systematic Errors: Systematic or Non-Random Errors are a constant or systematic bias in measurement.
What happens if error bars don't overlap? ›Confidence interval error bars
Useful rule of thumb: If two 95% CI error bars do not overlap, and the sample sizes are nearly equal, the difference is statistically significant with a P value much less than 0.05 (Payton 2003).
Select "More Options," choose "Custom" and then "Specify Value." Next, read the new "Custom Error Bars" menu, including the "Positive Error Value" and "Negative Error Value" inputs. Select each text box for these terms, delete their numbers and input custom positive and negative error terms in each.
Should I use standard error or standard deviation bars? ›When to use standard error? It depends. If the message you want to carry is about the spread and variability of the data, then standard deviation is the metric to use. If you are interested in the precision of the means or in comparing and testing differences between means then standard error is your metric.
Do you put error bars on histogram? ›You need to use a bar chart type, instead of histogram type to get error bars. Then you put the error bars on each bar.
Is it good or bad if error bars overlap? ›As a rule of thumb: If two data sets have comparable sample sizes and if the SE error bars of the two groups overlap then the two means cannot be considered significantly different. In general, if the SE error bars do not overlap one cannot say that the group means are significantly different.
Is it good if error bars overlap? ›Here is a simpler rule: If two SEM error bars do overlap, and the sample sizes are equal or nearly equal, then you know that the P value is (much) greater than 0.05, so the difference is not statistically significant.