document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1100900>Question 1100900</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a battery has a mean life of 320 hours and a standard deviation of 20 hours and by assuming that this distribution is normal, estimate the probability that the battery will last for more than 380 hours. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #715446 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=715446\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Probability(P) ( X > 380 ) = 1 - P( X < 380 )<BR>\n" );
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document.write( "z-value = (380 - 320) / 20 = 3<BR>\n" );
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document.write( "find in z-tables the probability associated with the z-value of 3<BR>\n" );
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document.write( "P( X < 380 ) = 0.9987<BR>\n" );
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document.write( "P( X > 380 ) = 1 - 0.9987 = 0.0013<BR>\n" );
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document.write( " </SPAN>\n" );
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