# openlab cds 2.5 calculation formulas

Hello,
Is it possible to determine the relative standard deviation of the average of the areas of the standards and the areas of the standards of the controls in sequence which are in 2 different resultsets
syb

• HI

Maybe a cross sequence summary report using tables with appropriate filters would do what you want.

Andy

• My request was not precise enough

What I would like is a formula that would do this calculation:
RELATIVE STANDARD DEVIATION (CurrentCalibrationCurve.AverageResponse(1); area of a control standard1; area of a control standard2;area of a control standard3)

For these two resultset :

resultset1 :
average area standards

resultset2 :
control standard1:area1
control standard2:area2
control standard3:area3

Is this possible with a custom formula?

• Hello,

You cannot do this in custom calculator, since CC cannot summarize data across result sets. You could do it in IR, but it might be a little complicated. Also this will only work if you want all the control standards or a roll up of the control standards, as I will demonstrate. It will not work to calculate the RSD of the standard average to each control.

First, I would create a table at the top, that will be hidden, filtered for the standard injections. I will store the peak area as a aggregator with compound_name as the category.   Second, I would create another table below the first that was filtered for my control standards and one injection from my cal standards. In this case, I used  =(Sample_Type = 4) Or (Sample_Type = 1 And Sample_Name = "SSS_1")  =  true as my filter, so that only the first cal standard will be in the table with the controls. In the peak area column, I set the value expression to  =If(Sample_Type = 1, Avg(StdArea(Compound_Name)),Peak_Area) so the cal standard would use the average of the agg values stored from the first table. I then stored that column as a aggregator to use in the final RSD column. You could also just use the column summary properties. I also did this as a comparison. The final image is the calculation done in excel for Peak A.    • thank you very much for this help

syb