# 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.

## Exceptions

## 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 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 https://go.microsoft.com/fwlink/?LinkId=219171.

## 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]))
```