document.write( "Question 1200778: A multiple-choice quiz has 15 questions, each with 4 possible answers, of which only 1is the correct answer. What is the probability that sheer guesswork yields from 5 to 10correct answers? \n" ); document.write( "

Algebra.Com's Answer #834990 by ikleyn(52788) $\"\"$ $\"About$

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\n" ); document.write( "A multiple-choice quiz has 15 questions, each with 4 possible answers,
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document.write( "With each individual question, the probability to guess the correct answer is  = 0.25.\r\n" );
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document.write( "Next, the problem is a typical binomial distribution problem\r\n" );
document.write( "with the number of trials n= 15, the number of success trials 5 <= k <= 10\r\n" );
document.write( "and the individual probability of success of 0.25.\r\n" );
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document.write( "So, in this problem \r\n" );
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document.write( "    P = P(n=15; 5 <= k <= 10; p=0.25) = P(n=15; k <= 10; p=0.25) - P(n=15; k <= 4; p=0.25).\r\n" );
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document.write( "At this point, you may use either your regular calculator TI-83/84 (function binomcdf)\r\n" );
document.write( "or free of charge online calculator at this web-site\r\n" );
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document.write( "https://stattrek.com/online-calculator/binomial.aspx\r\n" );
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document.write( "You will get then\r\n" );
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document.write( "    P = P(n=15; 5 <= k <= 10; p=0.25) = P(n=15; k <= 10; p=0.25) - P(n=15; k <= 4; p=0.25) = \r\n" );
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document.write( "                                      =         0.99988          - 0.68649 = 0.31339   (rounded).    ANSWER\r\n" );
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