The Power BI STDEV.P function is one of the DAX aggregate functions useful to calculate the standard deviation of the entire population. This article explains the DAX STDEV.P function that accepts the existing column (not the expression) to return the standard deviation of the entire population and the syntax is:
STDEV.P(<Column>)
The Power BI DAX STDEV.P function works only on the numeric values and assumes the column refers to the entire population. If it doesn’t have the entire population or sample of it, use the STDEV.S.
- The STDEV.P function uses the formula √[∑(x – x˜)2 / n] where x is the entire population, x˜ is the average, and n is the size of the population.
- While calculating the standard deviation of the entire population, the function will ignore the blank rows and it won’t be considered in the calculation.
- This function returns an error if the given column contains fewer than two non-blank rows. Refer to the DAX STDEV.S function.
Power BI DAX STDEV.P function Example
We need a Measure to work with the STDEV.P function and to assign the standard deviation of the entire population. So, within the Home tab, click the New Measure button and rename it as ProfitSTDEVP.
To demonstrate the DAX STDEV.P() function, use the Profit column from the SuperStore Orders table to obtain the standard deviation of the entire profit. Please refer to the Power BI Aggregate functions and Power BI DAX functions articles available on the Learn Power BI page for the remaining functions.
ProfitSTDEVP = STDEV.P(Orders[Profit])
Please add the new ProfitSTDEVP Measure to the Power BI table report. Similarly, create two more measures to calculate the standard deviation of the Sales and orders. For more charts, please refer to the Power BI Charts article.
SalesSTDEVP = STDEV.P(Orders[Sales])
OrdersSTDEVP = STDEV.P(Orders[Quantity])
