mean squared error (why mean?)

sunone

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.

micromass

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?

mathman

Quote by sunone

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.

Fix Latex.

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sunone	mean squared error (why mean?) Tweet 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.

micromass Blog Entries: 8 Recognitions: Gold Member Science Advisor Staff Emeritus	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?