# VAR.S Function (DAX)

Returns the variance of a sample population.

VAR.S(<columnName>)

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

A number with the variance of a sample population.

Exception | Condition |
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VAR.S assumes that the column refers to a sample of the population. If your data represents the entire population, then compute the variance by using VAR.P.

VAR.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 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 variance of the SalesAmount_USD column from the InternetSales_USD for a sample population.

=VAR.S(InternetSales_USD[SalesAmount_USD])