The Excel STDEV.P function calculates the standard deviation for a sample set of data. STDEV.P calculates standard deviation using the “n” method, ignoring logical values and text.
The STDEV.P function syntax has the following arguments:
- Number1 Required. The first number argument corresponding to a population.
Number2, … Optional. Number arguments 2 to 254 corresponding to a population. You can also use a single array or a reference to an array instead of arguments separated by commas.
Example: Let’s look at some Excel STDEV.P function examples and explore how to use the STDEV.P function as a worksheet function in Microsoft Excel:
A company keeps a record of its monthly sales figures, over the last three years. These are stored in cells B3-B14, D3-D14 and F3-F14 of the spreadsheet on the right .
The standard deviation of the three years’ sales figures is calculated in cell H3 of the spreadsheet. The formula for this, (shown in the spreadsheet formula bar), is:
In the example above, the arguments to the Stdev.P function are input as 3 cell ranges. However, you can also input figures directly, as individual numbers or number arrays.
For example, if, during January and February 2021 the sales figures are 14,000,000 and 15,500,000, you could add these directly into the above function as follows:
Or, as an array of numbers:
- STDEV.P assumes that its arguments are the entire population. If your data represents a sample of the population, then compute the standard deviation using STDEV.
- For large sample sizes, STDEV.S and STDEV.P return approximately equal values.
- The standard deviation is calculated using the “n” method.
- Arguments can either be numbers or names, arrays, or references that contain numbers.
- Logical values, and text representations of numbers that you type directly into the list of arguments are counted.
- If an argument is an array or reference, only numbers in that array or reference are counted. Empty cells, logical values, text, or error values in the array or reference are ignored.
- Arguments that are error values or text that cannot be translated into numbers cause errors.
- If you want to include logical values and text representations of numbers in a reference as part of the calculation, use the STDEVPA function.
- STDEV.P uses the following formula:
where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.