VAR.S Function (DAX)
Returns the variance of a sample population.
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.
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.