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    Hey,So in the Edexcel S3 book, chapter 3 examples 8 and 10, they're using this formula to calculate the estimated variance: (uploaded)

    Why is the denominator (n-1) instead of n as usual? Am I missing something completely obvious?


    Any help will be much appreciated thanks!
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    (Original post by Nikhilm)
    Hey,So in the Edexcel S3 book, chapter 3 examples 8 and 10, they're using this formula to calculate the estimated variance: (uploaded)

    Why is the denominator (n-1) instead of n as usual? Am I missing something completely obvious?


    Any help will be much appreciated thanks!
    there are 2 different formulas

    the one you are quoting is that of an unbiased estimator for the variance of a population, from a sample of n observations and it is denoted by s2
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    (Original post by TeeEm)
    there are 2 different formulas

    the one you are quoting is that of an unbiased estimator for the variance of a population, from a sample of n observations and it is denoted by s2
    Thanks!

    is there a proof of as to why it's 'n-1' instead of n?


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    (Original post by Nikhilm)
    Where did they specify that in the book? They didn't quote it in bold as usual?


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    Where?
    How will I know that ?

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    (Original post by TeeEm)
    Where?
    How will I know that ?

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    Lol I realised how stupid that reply was so I edited it but obviously not in time
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    (Original post by Nikhilm)
    Lol I realised how stupid that reply was so I edited it but obviously not in time
    no worries ... it is late!
 
 
 
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