document.write( "Question 470656: find the probability that exactly 5 of the 12 companies test for substance abuse\r
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\n" ); document.write( "\n" ); document.write( "80% test employees for substance abuse, the study involves the random selection of 12 companies \n" ); document.write( "

Algebra.Com's Answer #322833 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi,
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document.write( "Note: The probability of x successes in n trials is: 
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document.write( "P = nCx*  where p and q are the probabilities of success and failure respectively. 
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document.write( "In this case p(CO test) = .8  & q = .2
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document.write( "nCx = 
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document.write( "P(exactly 5 test) = 12C5(.8)^5(.2)^7 = 792(.8)^5(.2)^7 = .0033
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document.write( "P(at least half) = 1 - P(0)-P(1)-P(2)-P(3)-P(4)-P(5)= .9961
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document.write( "Recommend the use of a personal statistical calculator or using the calculators on sites such as: stattrek.com  \n" );
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