document.write( "Question 1176294: A civil service multiple-choice exam consists of 100 questions with 4 choices per question. Suppose a candidate randomly guesses the answer to every question. Find the probability that the candidate will answer less than 40 questions correctly \n" ); document.write( "

Algebra.Com's Answer #802898 by ikleyn(52876) $\"\"$ $\"About$

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document.write( "It is a binomial distribution probability problem.\r\n" );
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document.write( "     - number of trials        n =  100;\r\n" );
document.write( "     - number of success trial k <   40;\r\n" );
document.write( "     - Probability of success on a single trial p =  = 0.25.\r\n" );
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document.write( "We need calculate  P(n=100; k < 40; p=0.25).      \r\n" );
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document.write( "To facilitate calculations, I use an online (free of charge) 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( "It provides nice instructions  and  a convenient input and output for all relevant options/cases.\r\n" );
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document.write( "    P(n=100; k < 40; p=0.0.25) = 0.99931340779,   or   0.9993 (rounded).       ANSWER\r\n" );
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