STDEV.P Function (DAX)
Returns the standard deviation of the entire population.
STDEV.P assumes that the column refers to the entire population. If your data represents a sample of the population, then compute the standard deviation by using STDEV.S.
STDEV.P uses the following formula:
√[∑(x - x̃)²/n]
where x̃ is the average value of x for the entire 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.