# STDEV.S

Returns the standard deviation of a sample population.

## Syntax

STDEV.S(<ColumnName>)


### Parameters

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

## Return value

A number that represents the standard deviation of a sample population.

## Remarks

• STDEV.S assumes that the column refers to a sample of the population. If your data represents the entire population, then compute the standard deviation by using STDEV.P.

• STDEV.S uses the following formula:

√[∑(x - x̃)2/(n-1)]

where x̃ is the average value of x for the sample 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 measure that calculates the standard deviation of the column, SalesAmount_USD, when the table InternetSales_USD is the sample population.

= STDEV.S(InternetSales_USD[SalesAmount_USD])