# STDEV.P Function (DAX)

Returns the standard deviation of the entire population.

STDEV.P(<ColumnName>)

#### Parameters

columnName

The name of an existing column using standard DAX syntax, usually fully qualified. It cannot be an expression.

A number representing 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.

The following example shows the formula for a measure that calculates the standard deviation of the column, SalesAmount_USD, when the table InternetSales_USD is the entire population.

=STDEV.P(InternetSales_USD[SalesAmount_USD])