VARX.S Function (DAX)
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Returns the variance of a sample population.
VARX.S evaluates expression for each row of table and returns the variance of expression; on the assumption that table refers to a sample of the population. If table represents the entire population, then you should compute the variance by using VARX.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 calculated column that estimates the variance of the unit price per product for a sample population, when the formula is used in the Product table.
=VARX.S(InternetSales_USD, InternetSales_USD[UnitPrice_USD] – (InternetSales_USD[DiscountAmount_USD]/InternetSales_USD[OrderQuantity]))