document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=677849>Question 677849</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 40 multiple choice questions, 4 possible answers for each question, only one correct answer, if random guesses for all questions, what is the mean and standard deviation for number of correct answers?<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #421089 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=421089\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 40 multiple choice questions, 4 possible answers for each question, only one correct answer, if random guesses for all questions, what is the mean and standard deviation for number of correct answers?<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "mean = np = 40*(1/4) = 10<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "std = sqrt(npq) = sqrt(10*(3/4) = sqrt(7.5) = 2.7386\r<BR>\n" );
document.write( "\n" );
document.write( "=======================<BR>\n" );
document.write( "cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );