document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=581209>Question 581209</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Scores on a test have a mean of 63 and Q3 is 82.  The scores have a distribution that is approximately normal.  Find the standard deviation.  Round your answer to the nearest tenth. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #371526 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=371526\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Scores on a test have a mean of 63 and Q3 is 82. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth.<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Q3 has a left-tail of 0.75<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Find the corresponding z-score:<BR>\n" );
document.write( "invNorm(0.75) = 0.6745<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "Use x = zs+u to find \"s\":<BR>\n" );
document.write( "82 = 0.6745*s+63<BR>\n" );
document.write( "0.6745s = 19<BR>\n" );
document.write( "s = 19/0.6745<BR>\n" );
document.write( "s = 28.1694<BR>\n" );
document.write( "==================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );