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Math Help - Distribution and probability

  1. #1
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    Question Distribution and probability

    The parent distribution of x is normal with mean 80 and std. dev. 9

    sample size n = 25, mean (pop) of mean (samp) = 80, std dev (pop) of mean (samp) = 9/5 = 1.8
    _
    x = sample mean

    find
    A. P(62 < x < 80)
    _
    B. P(71 < x < 77)
    _
    C. x' such that P(x > x') = .05


    Thanks in advance if anyone can help me with this
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  2. #2
    MHF Contributor matheagle's Avatar
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    I did these earlier, see
    http://www.mathhelpforum.com/math-he...nt-sample.html
    but they asked the wrong question for part 3, it's easy to fix it, just use 1.645 instead of -1.645
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  3. #3
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    Quote Originally Posted by matheagle View Post
    I did these earlier, see
    http://www.mathhelpforum.com/math-he...nt-sample.html
    but they asked the wrong question for part 3, it's easy to fix it, just use 1.645 instead of -1.645
    Therefore, thread closed.
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