document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=506626>Question 506626</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Several students are unpreapred for a surprise true/false test with 9 questions and all of their answers are guesses.  Find the mean and standard deviation for the number of correct answers.  Would it be unusual for a student to p[ass by guessing and getting at least 4 correct answers? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #340245 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=340245\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Several students are unpreapred for a surprise true/false test with 9 questions and all of their answers are guesses. Find the mean and standard deviation for the number of correct answers. Would it be unusual for a student to pass by guessing and getting at least 4 correct answers?<BR>\n" );
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document.write( "Binomial Problem with n = 9 and p = 1/2<BR>\n" );
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document.write( "mean = np = 9*(1/2) = 4.5<BR>\n" );
document.write( "std = sqrt(npq) = sqrt[2.25] = 1.5<BR>\n" );
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document.write( "P(4<= x <=9) = 1-P(0<= x <=3) = 0.7461<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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document.write( " </SPAN>\n" );
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