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Math Help - Normal distibution.

  1. #1
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    Normal distibution.

    A pizza place offers 3 different cheeses and 12 different toppings. In how many ways can a pizza be made with 1 cheese and 3 toppings?
    A.198
    B.660
    C.1485
    D.2376

    The time required to finish a test in normally distributed with a mean of 40 minutes and a standard deviation of 8 minutes. What is the probability that a student chosen at random will finish the test in more than 56 minutes?
    A.84%
    B.2%
    C.34%
    D.16%

    What percentage of the data falls within 1 standard deviation of the mean?
    A.68%
    B.95%
    C.99%
    D.100%
    Last edited by mr fantastic; May 26th 2011 at 10:36 PM.
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  2. #2
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    Quote Originally Posted by Taylo17 View Post
    A pizza place offers 3 different cheeses and 12 different toppings. In how many ways can a pizza be made with 1 cheese and 3 toppings?
    A.198
    B.660
    C.1485
    D.2376
    Consider \displaystyle ^3C_1 and \displaystyle ^{12}C_3

    Quote Originally Posted by Taylo17 View Post

    The time required to finish a test in normally distributed with a mean of 40 minutes and a standard deviation of 8 minutes. What is the probability that a student chosen at random will finish the test in more than 56 minutes?
    A.84%
    B.2%
    C.34%
    D.16%
    \displaystyle \mu = 40 , \sigma = 8 , x=56

    \displaystyle z = \frac{x-\mu}{\sigma}

    What do you get?

    Now find \displaystyle P(Z>a)

    where 'a' is the result you found.



    Quote Originally Posted by Taylo17 View Post
    What percentage of the data falls within 1 standard deviation of the mean?
    A.68%
    B.95%
    C.99%
    D.100%
    There is no working to be done here, this is information your text book should provide.
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