document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199508>Question 1199508</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If a student is guessing randomly on a multiple choice test with 4 possible responses per question, and 16 questions:\r<BR>\n" );
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document.write( "What is the probability of getting 4 correct? </SPAN>\n" );
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document.write( "n = 16 = number of questions<BR>\n" );
document.write( "p = 1/4 = 0.25 = probability of success on any question<BR>\n" );
document.write( "x = 4 = number of desired successes\r<BR>\n" );
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document.write( "Use the binomial probability formula<BR>\n" );
document.write( "B(x) = (n C x)*p^x*(1-p)^(n-x)<BR>\n" );
document.write( "B(4) = (16 C 4)*0.25^4*(1-0.25)^(16-4)<BR>\n" );
document.write( "B(4) = (1820)*0.25^4*(1-0.25)^(16-4)<BR>\n" );
document.write( "B(4) = 0.22519906517119<BR>\n" );
document.write( "B(4) = 0.225199\r<BR>\n" );
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document.write( "There's about a 22.5199% chance of getting exactly four correct answers.\r<BR>\n" );
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document.write( "The nCx notation refers to the nCr combination formula.<BR>\n" );
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