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Percentange of bags rejected

  1. Jan 16, 2005 #1
    Hey guys, I've got this question from my Statistics Homework and wondered if someone could point me to a web site or supply some advice as to how to begin to solve the problem.

    Bags of sweets are packed by a machine such that the masses (X) have a normal distribution with mean 250g and standard deviation 10g.
    A bag is judged to be underweight and rejected if X<225g.
    A bag is judged to be overweight and rejected if X>270g
    What percentage of bags are rejected?

    I've tried a few combinations, but without a formula I don't think I'm making any sense. Can an altered version of the formula for Standard Deviation be used?

    Any help always appreciated : )

  2. jcsd
  3. Jan 16, 2005 #2


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    Science Advisor

    Underweight is 2.5 s.d. too low, while overweight is 2.0 s.d. too high. Look up a table of values for the normal distribution (not the density function, which is the bell curve).
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