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:
Okay got the linear regression correct, as in equal to the one qlikview calculates. But I still think the regression should be 112,875X - 111,875 not 72,30x + 150,44 as qlikview calculates. I think this has to do with the fact that a count of the orders in january returns null, as well as okt nov dec.