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October 4th, 2014, 02:09 AM  #1 
Newbie Joined: Oct 2014 From: UK Posts: 1 Thanks: 0  Reverse weighed average, I have the result but need the weightings
Sorry in advance if this is the wrong forum, my understanding of math and where to pidgeonhole it isn't so great. I'm trying to solve a problem which seems to follow the lines of weighted average, but in reverse. I already know the result, I need to find the weight of each of the contributing values. There are 16 values that contribute to the result, some sample data below, the result is in the first column: Code: 50 11000 11000 11000 1 35 35 99 60 60 99 60 99 99 2 0.5 520 50 11800 11800 11800 1 30 30 99 50 50 99 50 99 99 2 0.5 500 55 11800 11800 11800 1 35 35 10 10 10 99 10 10 99 2 0.55 550 55 12000 12000 12000 1 65 40 99 80 99 80 80 0 99 2 0.49 540 60 13000 13000 13000 1 50 35 15 80 80 15 80 99 99 2 0.6 600 60 11800 11800 11800 1 60 50 99 80 99 80 80 10 99 2 0.55 590 65 12300 12300 12300 1 35 60 15 80 80 80 15 15 99 2 0.6 620 Many thanks. PS Please don't put too much faith in the sample data, it's entered by hand and some doesn't look correct so would throw off the result calculation. Last edited by ezoray; October 4th, 2014 at 02:51 AM. Reason: spellin' 
October 16th, 2014, 02:46 PM  #2 
Newbie Joined: Apr 2014 From: MÃ©xico Posts: 10 Thanks: 0 Math Focus: Probability 
I think it might be useful to try to fit a linear model to your data. Read in the following wiki how do it Linear regression  Wikipedia, the free encyclopedia. Basically you need to apply the formula for Ordinary least squares.


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