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Math Help - Sampling Distributions Help

  1. #1
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    Sampling Distributions Help

    Suppose that a random sample is to be taken from a normal distribution for which the value of the mean Theta is unknown and the standard deviation is 2. How large a random sample must be taken in order that
    E[ |Xbar - theta|^2] <= 0.1 for ever possible value of theta?
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  2. #2
    MHF Contributor matheagle's Avatar
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    E[|\bar X - \theta|^2] is the variance of X bar

    and the variance of the sample mean is {\sigma^2\over n}

    So set {4\over n}\le .1
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  3. #3
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    Sampling Distributions Help - Again

    I was just curious as to how this problem would be solved if the question were changed to :

    E[ |Xbar - theta|]<= 0.1

    Thanks
    Last edited by mr fantastic; February 3rd 2010 at 12:41 AM.
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