Standard deviation of rolling sum of sales of product

[KJanssens]

My data consists of historical quantities sold each day of each product.

I have already calculated the rolling sum of products sold in a period, currently 30 days.

Measure 1:=CALCULATE(SUM([qty]); DATESINPERIOD('Calendar'[Date]; LASTDATE('Calendar'[Date]); -30; DAY))

Using this rolling sum, I want to detect products that are "Seasonal" products, where there are significant peaks in the rolling sum of quantity sold, versus "non-seasonal" products (where the rolling sum of the quantity of products sold is quite steady).

I am not a statistician, but I think I can use the standard deviation of this rolling sum for each product to detect products with peaks in its sales...

Any idea how I can do this in DAX?

Thanks,

Koen

[Mariusz]

Hi @KJanssens 

Try the below DAX functions.

STDEV.P	Returns the standard deviation of the entire population.
STDEV.S	Returns the standard deviation of a sample population.
STDEVX.P	Returns the standard deviation of the entire population.
STDEVX.S	Returns the standard deviation of a sample population.

Best Regards,
Mariusz

If this post helps, then please consider Accepting it as the solution.

[KJanssens]

Hi @Mariusz ,

I know these functions, but it seems I cannot just use it on the first measure:

Measure 2:= STDEV.P([Measure 1])

Any idea how I can do this?

[Mariusz]

Hi @KJanssens 

The argument that is expected is Column not Measure.

You can try using STDEVX.P this will allow you to pass a Measure as a second Argument

Best Regards,
Mariusz

If this post helps, then please consider Accepting it as the solution.