Monday, February 25, 2008

Average Puzzle

Average Puzzle
Suppose we have a set of N numbers, xi, and I want to choose an "average" value x*. There are many ways to define an average, but I have a particular requirement in mind. How should I choose the average value so that

1. I get the smallest possible value for the sum of the absolute values of the differences |xi-x*|;
2. I get the smallest possible value for the sum of the squares of the differences (xi-x*)2;
3. I get the smallest possible value for the maximum of the absolute values of the differences |xi-x*|;
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4 comments:

  1. Seeing the title of the puzzle, i assumed it to be a simple puzzle !!

    ReplyDelete
  2. 1. For odd N, it is (Nsquare -1)/4N

    For even N, it is N/4.

    ReplyDelete

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