standard deviation with fixed date

[leonardocapriglione]

Hey, Can you help me with some doubt?

I'd to make a standard deviation in a range date,

I use this :

=avg(aggr(SUM({<decision={'AP'}>}amount)/Sum(amount),date))

but in my graphic this formula gets the standard deviation variable, I would like to have the standard deviation in the fixed date in graph. Thanks,