STDEVX.P Function (DAX)
Returns the standard deviation of the entire population.
STDEVX.P evaluates expression for each row of table and returns the standard deviation of expression assuming that table refers to the entire population. If the data in table represents a sample of the population, you should compute the standard deviation by using STDEVX.S instead.
STDEVX.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.
The following example shows the formula for a calculated column that calculates the standard deviation of the unit price per product, when the formula is used in the Product table.
=STDEVX.P(RELATEDTABLE(InternetSales_USD), InternetSales_USD[UnitPrice_USD] – (InternetSales_USD[DiscountAmount_USD]/InternetSales_USD[OrderQuantity]))