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Math Help - Sampling question

  1. #1
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    Sampling question

    If N variables are normally distributed with the same mean and standard deviation, the true variance in the means among the N variables is zero. However, if the mean of each N_i is estimated from n samples, the estimated variance in the means among the N variables will be non-zero. What will the estimated variance be?

    Thanks for your answers.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by ecotheory View Post
    If N variables are normally distributed with the same mean and standard deviation, the true variance in the means among the N variables is zero. However, if the mean of each N_i is estimated from n samples, the estimated variance in the means among the N variables will be non-zero. What will the estimated variance be?

    Thanks for your answers.
    var(N_1)/sqrt(n)

    RonL
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  3. #3
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    Thanks captain, but could you either generalize to more than one N_i, or offer a hint of explanation for your answer so that I might? I guess I should have specified that the true variance of each N_i is also estimated from the samples.
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