Standard Deviation

Hi All,

My Fact has ItemKey,CompanyKey,MonthKey,Revenue

is there anway to calculate 'StDev.P' with resepect to itemnumbers from Item Dimension and MonthNumbers from Date Dimension.

where revenue for each and every month numbers will be the values to calculate 'Stdev.P' for individual item.

they should not respect Companykey in the fact as if it consider company then 1 item may repeat in different companies and will calculate stdev.p for individual company which i dont want.

Let’s be specific.

I have Fact table with

Fact(ItemKey,CompanyKey,MonthKey,Revenue)

DimDate(YearKey,MonthKey,MonthNumber)

DimItem(ItemKey,ItemNumber,ItemName)

DimCompany(CompanyKey,CompanyCode,CompanyName)

Created  Summary table as follows:

1. Method (without filters)

A=Summarize(‘Fact’,DimItem[ItemNumber],DimDate[MonthNumber],”Revenue”,SUM(‘Fact’[Revenue]))

B=Summarize(‘A’,’A’[ItemNumber],”Revenue”,Sum(‘A’[Revenue]),Stdev.P(‘A’[Revenue]))

‘A’ Summary for 1 Item

‘B’ Summary for 1 Item

 2. Method (I need company filter to be applied on the table so I am bringing CompanyCode also)

A=Summarize(‘Fact’,DimItem[ItemNumber],DimCompany[CompanyCode],DimDate[MonthNumber],”Revenue”,SUM(‘Fact’[Revenue]))

B=Summarize(‘A’,’A’[ItemNumber],’A’[CompanyCode],”Revenue”,Sum(‘A’[Revenue]),Stdev.P(‘A’[Revenue]))

‘A’ Summary for 1 Item

‘B’ Summary for 1 Item

Now when I drag CompanyCode from (2.Method ‘B’) and try to filter I can filter it in proper way, but when nothing is selected the standard deviation should be calculated as ‘208.55’ which is correct from (1.Method ‘B’), But I am getting ‘253.76’ which is the total of the three standard deviations.

What should I do to get standard deviation to be 208.55 when I don’t select any Company?

My requirement is to filter on the results, if I use 1.Method then I am unable to filter on companies even though there is join between Fact and DimCompany.

What did I miss?

am I not doing it in write way?

Please help me out with this.!!

Thanks in advance.