How to Do Error Bars on a Line Graph

1. Open the Excel 2010 spreadsheet that holds your line graph.
2. Click anywhere on the line graph to select it, then click the 'Layout' tab on top of the window, near the right end.
3. Locate the drop-down box in the 'Current Selection' area of the ribbon. Click the box and choose the data series that you want to display with error bars. To display all of your data series with error bars, choose 'Plot Area.'
4. Click the 'Error Bars' button in the 'Analysis' area of the ribbon. From the menu that appears, choose to add error bars for the standard error, for one standard deviation or for a 5 percent error on each value. If you want more precise control, choose 'More Error Bar Options,' then choose a data series from a small window that appears, as you can only add error bars this way for one series at a time. If you choose this option, another window appears.
5. Click the radio button next to 'Both,' 'Minus' or 'Plus' under the 'Direction' heading to determine which way your error bars will appear from the line on the graph. Under the 'End Style' heading, choose either to add or not to add a cap on the end of the bar.
6. Select your method for determining the error bar size under the 'Error Amount' heading. If you choose 'Fixed Amount,' 'Percentage' or 'Standard Deviation,' enter an amount into the box next to the option. You can also choose 'Standard Error,' but this option has no entry box, as the error bar sizes are determined solely by the values.
7. Change the appearance of the error bars from the 'Line Color,' 'Line Style,' 'Shadow' and 'Glow and Soft Edges' menus from the left side of the window. Each of these menus has numerous options to specify the exact look of the bars. Click 'Close' at the bottom of the window when done. Your error bars appear on the line graph.