document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1135693>Question 1135693</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Company XYZ knows that replacement times for the portable MP3 players it produces are normally distributed with a mean of 4 years and a standard deviation of 0.6 years.\r<BR>\n" );
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document.write( "Find the probability that a randomly selected portable MP3 player will have a replacement time less than 2.3 years? P(X<2.3 years) = ____\r<BR>\n" );
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document.write( "Answer accurately to 4 decimals. Answers obtained using exact z-scores or z-scores rounded to 3 decimals places are accepted.\r<BR>\n" );
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document.write( "If the company wants to provide a warranty so that only 3% of the MP3 players will be replaced before the warranty expires, what is the time length of the warranty? Warranty = ___ years\r<BR>\n" );
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document.write( "Answer accurately to 1 decimal. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #753357 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=753357\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "for x<2.3 years, z<=-1.7/0.6=-2.833<BR>\n" );
document.write( "This probability is 0.0023\r<BR>\n" );
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document.write( "z-score for 0.03 is -1.881<BR>\n" );
document.write( "-1.881=(x-4)/0.6<BR>\n" );
document.write( "x=2.871 years<BR>\n" );
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