Calculate std dev using set analysis

[kavirao]

Hi

I have requirement where i need to calculate stdev for below table for each quarter for listed companies for both selected companies and not selected companies separately.  
Eg (A,B,C,D,E,F)

If I have selected A,B,C  companies Std calculates.  =Stdev(Aggr(Sum(Sales),Company,QUARTER)).  Its working fine. 

 But  I couldnt able write expression for non selected companies D,E,F  for stdev expression failing   =Stdev(Aggr({<Company = e(Company)>} Sum(Sales),Company,QUARTER))

Any suggestion to write set analysis on this would be great help

Company	Q1	Q2	Q3	Q4
D	8	4	0	7
E	2	0	5	2
F	0	3	0	0
Total	11	9	10	15
STDev

[MarcoWedel]

maybe

Stdev({<Company = e()>} Aggr(Sum({<Company = e()>} Sales),Company,QUARTER))

?

[kavirao]

Its Not working. 

[MarcoWedel]

A short example using this expression:

Can you describe your expected results in this case?

[kavirao]

Thanks its working, Could you help me to put this into table irrespectively for all quarters i need to calculate like below.

A     2 /3,61

B    10/3,61

C     6/3,61

D     2/4,00

E     4/4,00

F      9/4.00