STDEV.S Function (DAX)
Returns the standard deviation of a sample population.
STDEV.S assumes that the column refers to a sample of the population. If your data represents the entire population, then compute the standard deviation by using STDEV.P.
STDEV.S uses the following formula:
√[∑(x - x̃)²/(n-1)]
where x̃ is the average value of x for the sample population
and n is the population size
Blank rows are filtered out from columnName and not considered in the calculations.
An error is returned if columnName contains less than 2 non-blank rows.
This DAX function may return different results when used in a model that is deployed and then queried in DirectQuery mode. For more information about semantic differences in DirectQuery mode, see http://go.microsoft.com/fwlink/?LinkId=219171.