Average Standard deviation calculated per month

[BobKoenen]

Hi I want to calculate a montly standard deviation 

I want to calculate the standard devation in DAX from my fact table but not the SD per row but totalled per month. 
My data looks like this 

Customer	date	Sales
A	1-1-2023	20
A	15-1-2023	50
A	5-2-2023	10
A	10-3-2023	150
B	1-1-2023	50
B	5-3-2023	1

Now I want a DAx formula which first calculates the total sales per month. e.g. for customer A see below and after that calculates the standard deviation per month. 

Customer	Month	Sales
A	1-2023	70
A	2-2023	10
A	3-2023	150

If i would calculate the st dev using 

STDEV.P(Tabel[Sales])  this gives me 57.35 which is 

[Anonymous · Accepted solution]

Hi @BobKoenen ,

According to your description, here are my steps you can follow as a solution.

(1) My test data is the same as yours.

(2) We can create a calculated column.

Month = FORMAT('Table'[date],"yyyy-mm") 

(3)We can create a measure.

Measure = calculate(STDEV.P('Table'[Sales]) , filter(allselected('Table'), 'Table'[Month] =max('Table'[Month])))

(4) Then the result is as follows.

If the above one can't help you get the desired result, please provide some sample data in your tables (exclude sensitive data) with Text format and your expected result with backend logic and special examples. It is better if you can share a simplified pbix file. Thank you.

Best Regards,

Neeko Tang

If this post  helps, then please consider Accept it as the solution  to help the other members find it more quickly. 

[some_bih]

Hi @BobKoenen one altenative is to use function  STDEVX.P, link STDEVX.P function (DAX) - DAX | Microsoft Learn

Create Date table and connect it to get monthly view in table with slicer for months and customer, also measure. You did not provide data what you expect as your sample is practically useless. Hope this help