document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=543895>Question 543895</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 5. 	A component of a precision instrument is subject to random failure. The time to failure of the component, or its productive life, is normally distributed with a mean of 440 hours and a standard deviation of 25 hours.   The production engineer would like to replace the component prior to failure after a certain number of productive hours.   He is willing to take a 1% chance that the component fails prior to this scheduled replacement time.\r<BR>\n" );
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document.write( "(a)	Should the replacement time be less than or greater than the mean time to failure?<BR>\n" );
document.write( "(b)	What replacement time should he select in this case?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #354963 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=354963\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A component of a precision instrument is subject to random failure. The time to failure of the component, or its productive life, is normally distributed with a mean of 440 hours and a standard deviation of 25 hours. The production engineer would like to replace the component prior to failure after a certain number of productive hours. He is willing to take a 1% chance that the component fails prior to this scheduled replacement time.<BR>\n" );
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document.write( "(a) Should the replacement time be less than or greater than the mean time to failure?<BR>\n" );
document.write( "Less than.<BR>\n" );
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document.write( "(b) What replacement time should he select in this case?<BR>\n" );
document.write( "Find the z-value with a left-tail of 1%<BR>\n" );
document.write( "invNorm(0.01) = -2.3263<BR>\n" );
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document.write( "Find the corresponding x-value:<BR>\n" );
document.write( "x = zs+u<BR>\n" );
document.write( "x = -2.3263**25+440 = 381.84 hours<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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