Cognos Report Studio Standard Deviation after aggregation?
I currently have a query that is calculating for [core task] [task family] mapping pairs the volume and the amount of time it takes to process. 

Example: 
[user] [core task] [task family] [volume] [Time Taken] 
1 MK - Investments     DO           1          200 
1 MK - Investments     DO           1          400 
2 MK - Investments     DO           1          100 
2 MK - Investments     DO           1          300 

note: time taken is in seconds 
I have a field working out the average throughput rate per hour called [Throughput CSP] which is calculated by 

(60/(([Time Taken] / [volume])/60)) - working out how many per hour they can get through. 

I brought through to a list on a page which gives per csp and core task and task family mapping set a [Throughput CSP] 

For example: 

[user] [core task] [task family] [Throughput CSP] 
1 MK - Investments      DO             12 
2 MK - Investments      DO             18 

I want to do the standard deviation on the Throughput CSP after aggregation (SD on 12 and 18). I have tried standard-deviation([Throughput CSP] for [Core Task],[Task Family])) so we get a standard deviation on the 12 , 18 but this is coming up with the standard deviation of each of the original 4 records standard deviation so: 

Standard deviation of: 

36, 18, 72 and 24 

Anyone have an idea how I can get the standard deviation to occur after cognos aggregates and calculates per CSP the [Throughput CSP]? 
Cognos Report Studio Standard Deviation after aggregation?
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I currently have a query that is calculating for [core task] [task family] mapping pairs the volume and the amount of time it takes to process. 

Example: 
[user] [core task] [task family] [volume] [Time Taken] 
1 MK - Investments     DO           1          200 
1 MK - Investments     DO           1          400 
2 MK - Investments     DO           1          100 
2 MK - Investments     DO           1          300 

note: time taken is in seconds 
I have a field working out the average throughput rate per hour called [Throughput CSP] which is calculated by 

(60/(([Time Taken] / [volume])/60)) - working out how many per hour they can get through. 

I brought through to a list on a page which gives per csp and core task and task family mapping set a [Throughput CSP] 

For example: 

[user] [core task] [task family] [Throughput CSP] 
1 MK - Investments      DO             12 
2 MK - Investments      DO             18 

I want to do the standard deviation on the Throughput CSP after aggregation (SD on 12 and 18). I have tried standard-deviation([Throughput CSP] for [Core Task],[Task Family])) so we get a standard deviation on the 12 , 18 but this is coming up with the standard deviation of each of the original 4 records standard deviation so: 

Standard deviation of: 

36, 18, 72 and 24 

Anyone have an idea how I can get the standard deviation to occur after cognos aggregates and calculates per CSP the [Throughput CSP]? 