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.
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 spreadsheet function instead.

The standard deviation is calculated using the "nonbiased" or "n1" 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.
St1 
St2 
St3 
St4 
St5 
St6 
St7 
St8 
St9 
St10 
Formula 
Description (Result) 
1345 
1301 
1368 
1322 
1310 
1370 
1318 
1350 
1303 
1299 
=STDEVA([St1], [St2], [St3], [St4], [St5], [St6], [St7], [St8], [St9], [St10]) 
Standard deviation of breaking strength for all the tools (27.46391572) 