## How does the STDEVX.P function (DAX) work?

The STDEVX.P function (DAX) returns the standard deviation of the entire population.

## STDEVX.P Formula Syntax

STDEVX.P(
<table>, <expression
)

## How do you use the STDEVX.P function?

This function is used to estimate standard deviation based on the entire population that results from evaluating an expression for each row of a table.

## Related Support Forum Posts

Difference between stdev measures that are similar
Confusion in using “Thin and Long Fact Table”
Dax Calculation question

## Considerations when using the STDEVX.P function

1. 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.
2. STDEVX.P uses the following formula:√[∑(x – x̃)²/n]where x̃ is the average value of x for the entire populationand n is the population size
3. Blank rows are filtered out from columnName and not considered in the calculations.
4. 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.

## Formula examples using the STDEVX.P function

=STDEVX.P(RELATEDTABLE(InternetSales_USD), InternetSales_USD[UnitPrice_USD] – (InternetSales_USD[DiscountAmount_USD]/InternetSales_USD[OrderQuantity]))

= STDEVX.P (Sales,[Sales Amount])