# STDEVA

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). Text and logical values such as TRUE and FALSE are included in the calculation.

**Syntax**

**STDEVA**(**value1**,value2, ...)

**Value1**,value2, ... are 1 to 30 values 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**

- STDEVA assumes that its arguments are a sample of the population. If your data represents the entire population, you must compute the standard deviation using STDEVPA.
- Arguments that contain TRUE evaluate as 1; arguments that contain text or FALSE evaluate as 0 (zero). If the calculation must not include text or logical values, use the STDEV worksheet function instead.
- The standard deviation is calculated using the "nonbiased" or "n-1" method.
- STDEVA uses the following formula:

**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 sample values (1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299) are stored in A2:E3, respectively. STDEV estimates the standard deviation of breaking strengths for all the tools.

`STDEV(A2:E3)`

equals 27.46