Issue calculating standard deviation

[jarrad_murray]

Hi All,

I am having an issue with calculating a standard deviation from a record level table.

I have a table with the following aggregated values 243, 309, 452, ,587, ,580, ,447, ,540, ,560, ,518, ,565, ,584, ,613, ,462, ,455. Performing a standard deviation calucation on this gives me a figure of 108.89

Using the code '=Stdev(aggr(sum({<PODGroup4Description = {'AandE'}>}ActivityActual), MonthYear))' gives me the figure 262.76

Has anyone encountered this before or does anyone have an idea as to what I am doing wrong.

Any help is greatly appreciated.

[Clever_Anjos]

If you need to agregate that table, you´re using a AGGR() as an expression

[Clever_Anjos]

Usefull reading: Pitfalls of the Aggr function

[Anil_Babu_Samineni]

Perhaps This?

=Stdev(aggr(sum({<PODGroup4Description = {'AandE'}>}ActivityActual), MonthYear, ActivityActual))

[Frank_Hartmann · Accepted solution]

I think the problem is that you dont set a Filter on MonthYear.

In your Textbox expression the Stdev is accounted for all the values in Field "MonthYear".

But the values you are showing in chart are restricted in MonthYear . So just set a Filter in Month Year as shown in attached sample or use SetAnalysis for filtering in MonthYear.

hope this helps

[jarrad_murray]

Hi Frank,

This is fantastic.  I didn't think the non available months would play a part in this.

Thank you very much.