Calculates standard deviation based on the entire population given as arguments (ignores logical values and text).
The standard deviation is a measure of how widely values are dispersed from the average value (the mean).
Syntax
STDEV.P(number1,[number2],...])
The STDEV.P function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):
 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.
Remarks
 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.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?
 Select the example in this article. If you are copying the example in Excel Online, copy and paste one cell at a time.
Important: Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 Create a blank workbook or worksheet.
 In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Online, repeat copying and pasting for each cell in the example.
Important: For the example to work properly, you must paste it into cell A1 of the worksheet.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

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A 
Strength 
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1322 
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Formula 
Description (Result) 
=STDEV.P(A2:A11) 
Standard deviation of breaking strength, assuming only 10 tools are produced (26.05455814) 
