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Ram31 Principal Member
Joined: 29 Nov 2004
Posts: 103

Posted: Fri Feb 18, 2005 10:40 am Post subject: problem in standard deviation & %Coefficient of variatio 


Hi,
I have two issues:
1. Standard Deviation
I want to calculate the standard deviation for a sample for which i have i created a stdddev(sample) measure object in the universe.
THe problem is when i run the report for stddev i get the values of each sample as follows:
15.75
0
121.68
6.68
0
0
113.57
11.47
0
101.8
57.74
0
507,006.84
At the end(last row) the value is not related to any sample. i am unable to figure out what is this value. i ran the query on my DB and i am getting the correct values but not the last row value which is neither the avg,sum or any other function i can think of. anyone had a similar experience. pls let me know.
2. The %Coefficient of Variation(%Cv)
Again when i calculate the %CV i am facing the same problem.i get a high value in the last row which i am not able to figure out.
The %CV=(Stddev(sample)/Avg(sample))*100
Thanks in advance
Ram
BO 5.1.3 Full client and Oracle8i 

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SteveBickerton Forum Associate
Joined: 15 Aug 2002
*5 Posts: 544 Location: Ottawa

Posted: Wed Feb 23, 2005 5:12 pm Post subject: Re: problem in standard deviation & %Coefficient of vari 


You need to use calculation contexts in both cases. I've used in Block because I don't know the dimensions you're using. You may need to alter this depending on what you're doing however (eg do you want to cross section breaks or report breaks).
1. Standard Deviation:
Populate a column with the following logic:
=StdDev(<measure>) In Block
The sample are the measure values in the block. You'll notice that StdDev(<measure>) , when it is placed in the footer, matches the column value of =StdDev(<measure>) In Block .
2. Convert your formula with calculation contexts to use summary metrics.
Average = Average(<measure>) In Block
Std dev = StdDev(<measure>) In Block
Hope this helps.
Steve _________________ www.noscentia.com 

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