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Math Help - T confidence interval

  1. #1
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    T confidence interval

    X1, X2,...Xn come from a random sample that is normally distributed with mu unknown and sigma^2 known. the confidence coefficient is .95 and the length of the confidence interval is less than .01*sigma. What is n?

    I got a weird answer of 120<n<infinity. is this wrong?
    Last edited by holly123; March 13th 2011 at 09:42 PM.
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  2. #2
    MHF Contributor matheagle's Avatar
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    (1) If sigma is known, you should be using a N(0,1) distribution and not a t.

    (2) I guess this CI is for MOO, I mean mu, you need to say what we are estimating.
    it could be one over mu, mu squared, sigma times moo.....

    (3) If so, set

    2{1.96\sigma\over \sqrt{n}}< {\sigma\over 100}
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