document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=851666>Question 851666</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The distribution of weights in a large group is approximately normally distributed. The mean is 80 kg and approximately 69% of the weights are between 70 and 90 kg. The standard deviation of the distribution of weights is equal to: </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #512915 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=512915\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  The distribution of weights in a large group is approximately normally distributed. The mean is 80 kg and approximately 69% of the weights are between 70 and 90 kg. The standard deviation of the distribution of weights is equal to:<BR>\n" );
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document.write( "Find the z-values that bracket 69% of the data around the mean.<BR>\n" );
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document.write( "Find the z-value with a left tail of (0.5-(0.69/2)) = 0.155<BR>\n" );
document.write( "invNorm(0.155) = -1.0152)<BR>\n" );
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document.write( "Use x = z*s + u to solve for \"s\"<BR>\n" );
document.write( "70 = -1.0152s + 80<BR>\n" );
document.write( "1.0152s = 10<BR>\n" );
document.write( "s = 9.85..<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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