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Math Help - probability 2

  1. #1
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    probability 2

    A very large shipment of parts contains 10% defectives. Two parts are chosen at random from the shipment and checked. Let X denote the numebr of defectives found. Find the probability function if this random variable.

    Please help me. Probability is killing me.
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  2. #2
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    In a large enough population we can assume that selections are independent. Then we can use binominal distribution. In this case, the probability of getting a defective part is 0.10. If we sat X is the number of defective parts in a sample of two then X can have three values: 0, 1, 2.
    Then the function is: f(x) = { 2 \choose x } \left( {0.1} \right)^x \left( {0.9} \right)^{2 - x}
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  3. #3
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    Thank you so much, Plato.
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