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March 28th, 2019, 04:02 AM  #1 
Newbie Joined: Mar 2019 From: London Posts: 1 Thanks: 0  Weighted Average question
Hey, I am trying to read up on the term Weighted Average. In doing this I found the following article posted by Investopedia: https://www.investopedia.com/terms/w...tedaverage.asp My question is. Isen't there an error in the table calculation? The article states that the weighted average is 130. But wouldn't it be 39? Combined value of 390 divided by the combined weight of 10. And the simple average being 100/3 = 33,3? I might have misunderstood it, but I was hoping someone on this forum might help enlighten me on the question. 
March 28th, 2019, 06:36 AM  #2 
Senior Member Joined: Sep 2015 From: USA Posts: 2,590 Thanks: 1434 
I agree. You divide the sum of the weighted data points by the sum of the weights to obtain the weighted average. Usually in a situation like this you insist up front that the sum of the weights be 1 They can always be normalized so this isn't a problem. 

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