document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199511>Question 1199511</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 9 correct? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #833433 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13203)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=833433\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The number of ways of \"choosing\" 9 of the 16 questions to be the ones that are answered correctly is C(16,9) = \"16 choose 9\".<br><BR>\n" );
document.write( "For each of those ways, the probability of 9 right and 7 wrong is (1/4)^9 * (3/4)^7.<br><BR>\n" );
document.write( "ANSWER:  (use a calculator....)<br><BR>\n" );
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document.write( "Answer the other several questions you have submitted the same way.<br><BR>\n" );
document.write( "For a question like \"getting AT LEAST\" 6 right, you will need to perform the calculations for 6, 7, 8, ..., and 16 right and add the probabilities for the separate cases.  That is a huge amount of work; most good calculators like a TI-84 have built-in capabilities for getting the answer with a few quick inputs.<br>\r<BR>\n" );
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