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Mean squared error (why mean?)

  1. Mar 3, 2013 #1
    Hi
    I found this equation in a machine learning book:
    "we want to minimize the mean squared error:"
    $E= \frac{1}{2} \sum_{n=1}^N (y-t)^2$

    what I do not understand is the \frac{1}{2} , if it is a mean it should be \frac{1}{N},
    why are they restricting to 2? In the text there is no reference to y or t being only 2. So it cannot be that N=2.
     
  2. jcsd
  3. Mar 3, 2013 #2

    micromass

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    If you ask a question here, please always be sure to include the necessary reference. What book did you read this in? Title, author, page number?
     
  4. Mar 3, 2013 #3

    mathman

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    Fix Latex.
     
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