How To Calculate Standard Deviation In Power Bi

How to Calculate Standard Deviation in Power BI

Definition:

The standard deviation is a statistical measure that calculates the extent to which data points in a distribution deviate from the mean. It is useful for understanding the variability or dispersion of a set of values. In Power BI, you can calculate the standard deviation using built-in functions.

Step-by-Step Guide:

1. Ensure that you have your data imported into Power BI and the desired table or column is accessible.
2. Create a new measure or column to calculate the standard deviation. To do this, right-click on a table and select “New Measure/Column” or open the formula bar in Power Query Editor.
3. In the formula bar, use the appropriate DAX function to calculate the standard deviation. The three commonly used functions are:
   • STDEV.P: This function calculates the standard deviation considering the entire population.
   • STDEV.S: This function calculates the standard deviation considering a sample of the population.
   • STDEVPQ: This function calculates the standard deviation considering the entire population, available in Power Query Editor.

   For example, if you have a table named “Sales” and want to calculate the standard deviation of the “Quantity” column, the formula using STDEV.P would be:

           Sales Standard Deviation = STDEV.P(Sales[Quantity])
         

4. Press Enter to apply the formula.
5. The calculated standard deviation will be displayed in the table or visualization.

Example:

Let’s consider a sales dataset with the following columns: “Product”, “Quantity”, and “Price”. To calculate the standard deviation of the quantity sold, follow these steps:

1. Import the sales data into Power BI.
2. Open Power Query Editor.
3. Click on the “Sales” table.
4. Click on “New Measure” or “New Column” based on your requirement.
5. In the formula bar, enter the formula:

      Sales Standard Deviation = STDEV.P(Sales[Quantity])
    

6. Press Enter to apply the formula.
7. Close Power Query Editor and return to the report view.
8. Drag and drop the “Sales Standard Deviation” measure into a visual or table.
9. The standard deviation of the quantity sold will be displayed in the visual or table.

By following these steps, you can calculate the standard deviation of any column in your Power BI dataset. It helps in analyzing the dispersion and variability of the data.