7 Replies Latest reply: Oct 19, 2015 3:32 PM by Ruud Cruchten RSS

    Linear regression Linest_M + Linest_B

    Ruud Cruchten

      Hi all,

       

      I want to forecast the amount of orders for the coming months. I've created a master calendar which adds dates for + 1 year after the max date in the data (so that I can forecast multiple months ahead).

      However, the linest_m and linest_b aren't calculating the correct numbers.

      To calculate the forecast I'm using the following functions:

       

      (LINEST_M( TOTAL Aggr(Count([Werkorder partner]), [Maand melding]), [Maand melding]) * NUM([Maand melding]) )+

       

      LINEST_B(TOTAL Aggr(Count([Werkorder partner]), [Maand melding]), [Maand melding])

       

      As you can see the X is 72,30, when I calculate it manually however I get: 903 / 8 = 112,875 and B -111,875.

       

      I've tried forcing the graph to start in (0,0) with

      (LINEST_M( TOTAL Aggr(Count([Werkorder partner]), [Maand melding]), [Maand melding],0,0)

      but this returns x as 6945,5948???

      The correct formula (I think) should be: 112,875X - 111,875. Just have to get qlik to understand that