Excel makes it easy to calculate standard deviation thanks to its =STDEV() function, but before you rush off to try it out in your spreadsheet, bear in mind that it will probably give you six options for the function. Here we’ll show you how to calculate standard deviation in Excel and which function to use. See also:
How to use Excel
How to get free Microsoft Office 2016
We’re using Excel 2013 here, but it’s the same or similar in other versions.
How to calculate standard deviation in Excel: the basics
Let’s say you have a column full of data. All you need to do to calculate the standard deviation is select an empty cell on your spreadsheet, type =stdev(a1:a20) and you’ll get your answer instantly.
This assumes that your data is numerical values in cells A1 to A20.
How to calculate standard deviation in Excel: Which function to use
For the vast majority of cases, you’ll be working with samples, rather than populations. This narrows your choice of functions to just three: STDEV.S, STDEVA and STDEV
The latter is simply there for compatibility with Excel 2007 and earlier, which leaves just the first two. You’ll probably want to use STDEV.S as STDEVA is only where you’re dealing with non-numeric data (such as TRUE or FALSE answers, for example).
The other three functions, STDEV.P, STDEVPA and STDEVP are for population data. You’d only use these if you have data from every member of the population. If not, use the sample functions.
STDEV.P is the population equivalent of STDEV.S and is for numerical data, while STDEVPA will handle text as well. As you might be able to guess, STDEVP is only there for compatibility with Excel 2007 and earlier, so unless you need this for some reason, avoid using it.
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