standard deviation +3

[rcorcoran]

Hi I am trying to calculated the standard deviation from the mean by *sigma 3.  I am not very knowledgeable anyway on stats but the calculation below is giving me a figure but not the correct figure.  just wondering if anything sticks out as being wrong in the expression.

Thanks in advance

=Sum(total{<CIFCode={'18.166.11'}>}ActualValue)/Sum(total{<CIFCode={'18.142.16'}>}ActualValue)*10000+3*sqrt(Sum(total{<CIFCode={'18.166.11'}>}ActualValue)
/Sum(total{<CIFCode={'18.142.16'}>}ActualValue)*10000/Sum({<CIFCode={'18.142.16'}>}ActualValue)*10000)

[hallquist_nate]

Do you have a formula template that you are using? 

It looks like you probably don't have all of the Parenthesis in the right places.  if you have a template or something that that you can post that you are trying to follow, I might be able to give you a hand on this.

Nate