document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=199119>Question 199119</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Fast Service Truck Lines uses the Ford Super Duty F-750 exclusively. Management made a study of the maintenance costs and determined the number of miles travled during the year followed the normal distribution. The mean of the distribution was 60,000 miles and the standard deviation 2,000 miles.\r<BR>\n" );
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document.write( "a. What percent of the Ford Super Duty F-750's logged 65,200 miles or more?<BR>\n" );
document.write( "b. What percent of the trucks logged more than 57,060 but less than 58,280?<BR>\n" );
document.write( "c. What percent of the Fords travled 62,000 miles or less during the year?<BR>\n" );
document.write( "d. Is it reasonable to conclude that any of the trucks were driven more than 70,000 miles? Explain </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #149600 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=149600\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Fast Service Truck Lines uses the Ford Super Duty F-750 exclusively. Management made a study of the maintenance costs and determined the number of miles travled during the year followed the normal distribution. The mean of the distribution was 60,000 miles and the standard deviation 2,000 miles. <BR>\n" );
document.write( "a. What percent of the Ford Super Duty F-750's logged 65,200 miles or more?<BR>\n" );
document.write( "z(65200) = (65200-60000)/2000 = 5200/2000 = 2.6<BR>\n" );
document.write( "P(x>=65200) = P(z>=2.6) = 0.00466<BR>\n" );
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document.write( "b. What percent of the trucks logged more than 57,060 but less than 58,280?<BR>\n" );
document.write( "Find the z-values of each of these.<BR>\n" );
document.write( "Then find the fraction of the population that lies between those z-values<BR>\n" );
document.write( "I get 0.12411..<BR>\n" );
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document.write( "c. What percent of the Fords travled 62,000 miles or less during the year?<BR>\n" );
document.write( "same procedure<BR>\n" );
document.write( "I get: 0.8413...<BR>\n" );
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document.write( "d. Is it reasonable to conclude that any of the trucks were driven more than 70,000 miles? Explain\r<BR>\n" );
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document.write( "That figure is 5 standard deviations above the mean.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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