# STDEVX.S

Returns the standard deviation of a sample population.

## Syntax

STDEVX.S(<table>, <expression>)


### Parameters

Term Definition
table Any DAX expression that returns a single scalar value, where the expression is to be evaluated multiple times (for each row/context).
expression Any DAX expression that returns a single scalar value, where the expression is to be evaluated multiple times (for each row/context).

## Return value

A number with the standard deviation of a sample population.

## Remarks

• STDEVX.S evaluates expression for each row of table and returns the standard deviation of expression assuming that table refers to a sample of the population. If table represents the entire population, then compute the standard deviation by using STDEVX.P.

• STDEVX.S uses the following formula:

√[∑(x - x̃)2/(n-1)]

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 function is not supported for use in DirectQuery mode when used in calculated columns or row-level security (RLS) rules.

## Example

The following example shows the formula for a calculated column that estimates the standard deviation of the unit price per product for a sample population, when the formula is used in the Product table.

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