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    Name:  Screen Shot 2016-05-04 at 12.35.06.png
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Size:  19.9 KBPlease see screenshot - Could someone please explain to the me steps.

    In particular, why when taken outside of the sum does 1/n become 1/n2
    Then after that why does the o2 come into play?
    Help appreciated.
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    (Original post by JKITFC)
    Name:  Screen Shot 2016-05-04 at 12.35.06.png
Views: 46
Size:  19.9 KBPlease see screenshot - Could someone please explain to the me steps.

    In particular, why when taken outside of the sum does 1/n become 1/n2
    Then after that why does the o2 come into play?
    Help appreciated.
    If X is a random variable and a is a scalar, then var(aX) = a^2 var(x). Just look at the formula for variance. The \sigma^2 comes from the fact that the X_i are identically distributed each with variance \sigma^2
 
 
 
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