document.write( "Question 446473: A production line manufactures light bulbs with a defective rate of 0.05. What is the probability that in a batch of 20 light bulbs, 2 or more of them are defective? What is the probability that 1 or 2 bulbs are defective in the batch? \n" ); document.write( "

Algebra.Com's Answer #307479 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi,\r
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document.write( "A production line manufactures light bulbs with a defective rate of 0.05. What is P(in a batch of 20 light bulbs, 2 or more of them are defective)?\r
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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 = .05  and q = .95
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document.write( "nCx = 
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document.write( "P(2 or more defective) = 1 - P(none) - P(one) 
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document.write( "                       = 1 -(.95)^20 - 20(.05)^1*(.95)^19
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document.write( "                       = 1 - .3585 - .3774 = .2641
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document.write( "P( 1 or 2 are defective) = .3774 + .1887 = .5661 \n" );
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