document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1008087>Question 1008087</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A history quiz had 8 multiple choice questions.  Each question has 4 answer choices.  A student has forgotten that the quiz was to tale place and guesses at all of the answers.\r<BR>\n" );
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document.write( "a) Find the probability that the student gets exactly 5 of the 8 questions correct.\r<BR>\n" );
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document.write( "b) Find the probability that the student gets at least 6 questions correct. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #623834 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=623834\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> it is 8C5(0.25)^5(0.75)^3=0.0231<BR>\n" );
document.write( "For at least 6, we need 6,7,8<BR>\n" );
document.write( "6: 8C6(0.25^6)(0.75^2)=0.0038<BR>\n" );
document.write( "7: 8(0.25^7)*0.75=0.0008<BR>\n" );
document.write( "for 8, 0.25^8=0.00002<BR>\n" );
document.write( "The probability is 0.0046.<BR>\n" );
document.write( "The expected value is 2 with the variance 1.5. </SPAN>\n" );
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