document.write( "Question 1201802: A box of 30 flashbulbs contains 3 defective . A random sample of 2 is selected and tested. Let X be the random variable associated with the number of defective bulbs in the sample. ​(A) Find the probability distribution of X. \n" ); document.write( "
Algebra.Com's Answer #836315 by ikleyn(52780)\"\" \"About 
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\n" ); document.write( "A box of 30 flashbulbs contains 3 defective . A random sample of 2 is selected and tested.
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\n" ); document.write( "\n" ); document.write( "        As this problem is worded, it tells me that it assigned to a person
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document.write( "The random variable X may have one of three values: X= 0, 1, 2.\r\n" );
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document.write( "P(X=0) is the probability that a random sample of 2 flashbulbs contains 0 defective.\r\n" );
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document.write( "The probability for it is  P(X=0) = \"%2827%2F30%29%2A%2826%2F29%29\" = \"702%2F870\" = \"117%2F145\" = 0.806896552 (rounded).\r\n" );
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document.write( "P(X=1) is the probability that a random sample of 2 flashbulbs contains 1 defective.\r\n" );
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document.write( "The probability for it is  P(X=1) = \"2%2A%2827%2F30%29%2A%283%2F29%29\" = \"162%2F870\" = \"27%2F145\" = 0.186206897 (rounded).\r\n" );
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document.write( "P(X=2) is the complement of P(X=0) + P(X=1) to 1, so we calculate it this way \r\n" );
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document.write( "    P(X=2) = 1 - 0.806896552 - 0.186206897 = 0.006896551.\r\n" );
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document.write( "We can check the value P(X=2) this way  P(X=2) = \"%283%2F30%29%2A%282%2F29%29\" = \"2%2F290\" = \"1%2F145\".  117+27+1 = 145.  ! correct !\r\n" );
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