document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=108786>Question 108786</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with the following question:  (It is not in the book, it is on a homework assignment.)\r<BR>\n" );
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document.write( "The lifetime of a popular dvd player is guaranteed to be 8 years. If the lives of this dvd players are normally distributed with a mean of 8.75 and a SD of .45 years, find the percentage of the DVD players that will not meet the guarantee. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #79368 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=79368\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since you've assumed a normal distribution, you can <BR>\n" );
document.write( "calculate your z value using the value you're intereted in, the mean and the  standard deviation.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=z=%28x-x%5Bm%5D%29%2F%28sigma%29 ALIGN=MIDDLE  ALT=\"z=%28x-x%5Bm%5D%29%2F%28sigma%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "where x = 8 years (your warranty date)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=z=%288-8.75%29%2F%28.45%29 ALIGN=MIDDLE  ALT=\"z=%288-8.75%29%2F%28.45%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=z=-1.667 ALIGN=MIDDLE  ALT=\"z=-1.667\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Your z score then gives you the percentage of units that failed before 8 years, that is, did not meet the guarantee.<BR>\n" );
document.write( "At z=-1.667, the cumulative distribution function (from EXCEL) gives a value of 0.04779. <BR>\n" );
document.write( "In other words, from 0 to 8 years, the area under the curve is 4.8% of the total area. <BR>\n" );
document.write( "4.8% of the units failed to meet the guarantee. \r<BR>\n" );
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