Standard Deviation Error Bars can be used for a variety of data types – scores, investment performance, tracking your running stats, etc. Click and drag down the standard deviation values, then click OK, then Close and you should see error bars on your graph. Instead we will choose More Options, then click Custom and Specify Value:įor both Positive and Negative Error Values, click on the range button and highlight the row of Std Dev values:Ĭlick OK, and you will now see that the Std Dev Error Bars are properly proportional to the values, and indicate which had the widest and narrowest range of values: That is because Excel has determined the Std Dev for ALL the scores, not just for the individual courses. However, notice that they are all the same. If you hover over the Standard Deviation option, you will see them appear. Now, to add the Standard Deviation Error Bars, if in Excel 2013, click on the chart and select Chart Elements and go down to Error Bars (for 2010, look for Error Bars in the Analysis Group on the Layout Contextual tab). Now, how do we graph this to see it visually? First we'll start by charting the Average of each course: In contrast, the Bio score average was higher, but the Std Dev was the highest of all, confirming that the scores ranged from 66 to 94. This suggests that most of the students had similar struggles with the course content. As you can see by the chart, the math scores had the lowest average, but the smallest Std Dev. Standard Deviation is a great way to see the range of a set of data around the average. I've added the average for each course along with the Standard Deviation:Īlthough this is not intended to be an explanation of Standard Deviation, here are a few notes about it: Here we have a list of students and their test scores for four different classes.
If you see a preview, just look for the download arrow in the upper right hand corner. You can download the file here to follow along. Here is how you can visually see the variances from the average of a range of data using the Error Bars option for charts in Excel: