0 Replies Latest reply: Dec 4, 2012 4:43 AM by eduqlikview RSS

    EWMA - Regelkarte

      Hey!

       

      I would like to plot the following expression but I have some problems with the second therm:

      z_i = \lambda \bar x_i + \left ( 1 - \lambda \right)z_{i - 1}.

       

      Here I copy the explanation of the formula:

       

      "The EWMA chart computes successive observations zi by computing the rational subgroup average, \bar x_i, and then combining that new subgroup average with the running average of all preceding observations, zi - 1, using the specially–chosen weight, λ."

       

      My Data looks like this:

       

      DateValue
      2012.01.03 16:03:550,41
      2012.01.03 20:31:430,434
      2012.01.03 23:13:580,42
      2012.01.04 13:56:060,431
      2012.01.04 16:21:060,455
      2012.01.04 22:14:280,45
      2012.01.04 22:20:310,437
      2012.01.04 22:26:450,448
      2012.01.04 22:35:220,437
      2012.01.04 23:16:090,449
      2012.01.11 10:10:070,449
      2012.01.11 10:37:040,422

       

      The subgroups must be "days".

       

       

      Thank you very much!!! This chart is driving me crazy!

       

      Eduardo