document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1159160>Question 1159160</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 470 seconds and a standard deviation of 50 seconds. Between what times do we expect most (approximately 95%) of the boys to run the mile? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #783422 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=783422\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 95% is a z-score between -1.96 and 1.96<BR>\n" );
document.write( "z=(x-mean)/sd<BR>\n" );
document.write( "1.96=(x-570)/50<BR>\n" );
document.write( "x-470=98<BR>\n" );
document.write( "x=568 upper end (+98)<BR>\n" );
document.write( "x=372 lower end (-98)<BR>\n" );
document.write( "(372, 568) units seconds </SPAN>\n" );
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