document.write( "Question 655299: There are 20 multiple choice questions on a test with 5 possible answers each. Find the probability of guessing 15 questions out of 20 correct. Is this likely or unlikely? Why?\r
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\n" ); document.write( "\n" ); document.write( "P(15 correct out of 20 questions)= 20/15 (.20)^15 (.80)^5 \n" ); document.write( "

Algebra.Com's Answer #409051 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, Yes!  p = .20 & q = .80
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document.write( "P(15 correct out of 20 questions)= 20C15 (.20)^15 (.80)^5 = 15,504(.20)^15 (.80)^5= .00000017
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document.write( "Probability so...small, UNLIKELY \n" );
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