5 Replies Latest reply on Nov 27, 2012 4:44 PM by Aaron Rubinstein

    Calculating the Sum of a Weighted Percent Change

    Aaron Rubinstein

      In the attached workbook I am calculating the percent change in prices of two products over time, and I have weighted those percent changes based on the proportion of my overall cost that each product represents (Product A is 70%, Product B is 30%).

       

      What I am trying to do now is add an additional line to the chart that would show the sum of the weighted percent changes in Product A and Product B. In other words, for each date I need to add the weighted percent change in Product A to the weighted percent change in Product B, and chart that as a new line. I cannot figure out how to set this up correctly; any help would be appreciated.

       

      The correct values for the new line should be as follows:

       

      Date

      Overall % Change

      1/1/2011

      0.00%

      2/1/2011

      1.45%

      3/1/2011

      6.15%

      4/1/2011

      9.60%

      5/1/2011

      4.65%

      6/1/2011

      8.35%

      7/1/2011

      9.55%

      8/1/2011

      10.25%

      9/1/2011

      8.50%

      10/1/2011

      10.00%

      11/1/2011

      12.85%

      12/1/2011

      15.45%