5 Replies Latest reply on Sep 11, 2018 1:03 PM by Shinichiro Murakami

    How To:  Standard Deviation of a measure already being aggregated

    Stephen Groff

      Standard Deviation requires summing up all the data points in a set.

       

      In my case I'm trying to get the STD DEV for my defects per unit.

       

      Defects Per Unit = [Defects] / [Machines] Produced

       

      However, I created a calculation to get my number of [Defects], as well as created a calculation to get my # of [Machines].

       

      SUM([Defects] / [Machines] - cannot be further aggregated so I imagine I will have to change my initial calculations for both, summing them both up before hand... maybe??

       

       

      Not sure how I can sum this up since the # of machines is dependent on a distinct count of [Serial No]

      I think I can change the COUNTD from this measure and add in SUM then [Number of Records]

      Doesn't Tableau already have built-in calculations for all this?

       

      Any help or advice would be greatly appreciated.