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Math Help - Simple Central Limit Theorem question.

  1. #1
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    Simple Central Limit Theorem question.

    Suppose that samples of size are selected at random from a normal population with mean 100 and standard deviation 10. What is the probability that the sample mean falls in the interval from to ?

    I'm not sure if I did this correctly, have I made any mistakes?

    \sigmax = \frac{\sigma}{\sqrt{n}} = 2

    then for the lower interval I get 100-2.2(2) = 95.6
    and for the upper interval 100+1.2(2) = 102.4

    So P(95.6 < X < 102.4) --> P((95.6 - 100)/2 < Z < (102.4-100)/2) -->
    P(-2.2 < Z < 1.2) --> P(1.2) - P(-2.2) and from the Z chart
    0.884930 - 0.013903 = 0.871027
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  2. #2
    MHF Contributor matheagle's Avatar
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    fill in the red ex's
    This is not a central limit question since you do have normality
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