STDEV

See Also

Estimates standard deviation based on a sample. The standard deviation is a measure of how widely values are dispersed from the average value (the mean).

Syntax

STDEV(number1,number2,...)

Number1, number2, ... are 1 to 30 number arguments corresponding to a sample of a population. You can also use a single array or a reference to an array instead of arguments separated by commas.

Remarks

STDEV assumes that its arguments are a sample of the population. If your data represents the entire population, then compute the standard deviation using STDEVP.
The standard deviation is calculated using the "nonbiased" or "n-1" method.
STDEV uses the following formula:

Formula

Logical values such as TRUE and FALSE and text are ignored. If logical values and text must not be ignored, use the STDEVA worksheet function.

Example

Suppose 10 tools stamped from the same machine during a production run are collected as a random sample and measured for breaking strength.

The example may be easier to understand if you copy it to a blank worksheet.

How?

Create a blank workbook or worksheet.
Select the example in the Help topic. Do not select the row or column headers.

Selecting an example from Help
Press CTRL+C.
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Tools menu, point to Formula Auditing, and then click Formula Auditing Mode.

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A
Strength
1345
1301
1368
1322
1310
1370
1318
1350
1303
1299
Formula	Description (Result)
=STDEV(A2:A11)	Standard deviation of breaking strength (27.46391572)