document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1168080>Question 1168080</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The weight of a sophisticated running shoe is normally distributed with a mean of 12 ounces<BR>\n" );
document.write( "and a standard deviation of 0.5 ounces.<BR>\n" );
document.write( "a. What is the probability that a shoe weighs more than 13 ounces?<BR>\n" );
document.write( "b. What must the standard deviation of weight be in order for the company to state that 99.9%<BR>\n" );
document.write( "of its shoes are less than 13 ounces? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #792697 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=792697\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "=(13-12)/0.5=2 sd<BR>\n" );
document.write( "the probability is z>2 or 0.0228<BR>\n" );
document.write( "-<BR>\n" );
document.write( "99.9% is a z-value of 3.09<BR>\n" );
document.write( "so 3.09=(1)/sd<BR>\n" );
document.write( "so sd has to be 1/3.09 or 0.324 oz.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );