document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=586436>Question 586436</A>: <I><SPAN STYLE=\"word-break: break-all;\"> There were 20 multiple choice questions, each of which had only one correct answer from 4 choices. Assuming that she guesses on all 20 questions what is the probability that:<BR>\n" );
document.write( "A. Get all 20 right?<BR>\n" );
document.write( "B. Get exactly 14 questions (70%) right?<BR>\n" );
document.write( "C. Get at least 12 questions right?<BR>\n" );
document.write( "D. Get at least 14 questions right? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #373750 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=373750\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> There were 20 multiple choice questions, each of which had only one correct answer from 4 choices. <BR>\n" );
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document.write( "Binomial Problem with n = 20 ; p(correct) = 1/4 ; p(wrong) = 3/4<BR>\n" );
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document.write( "Assuming that she guesses on all 20 questions what is the probability that:<BR>\n" );
document.write( "A. Get all 20 right?<BR>\n" );
document.write( "P(x = 20) = (1/4)^20 = 9.1x10^-13<BR>\n" );
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document.write( "B. Get exactly 14 questions (70%) right?<BR>\n" );
document.write( "P(x = 14) = 20C14*(1/4)^14*(3/4)^6 = binompdf(20,0.25,14) = 0.0000257<BR>\n" );
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document.write( "C. Get at least 12 questions right?<BR>\n" );
document.write( "P(12<= x <=20) = 1 - binomcdf(20,0.25,11) = 0.0009354 <BR>\n" );
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document.write( "D. Get at least 14 questions right?<BR>\n" );
document.write( "P(14<= x <=20) = 1 - binomcdf(20,0.25,13) = 0.00002951<BR>\n" );
document.write( "======================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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