document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=800087>Question 800087</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the life span of a battery is normally distributed, with a mean of 2100 hours and a standard deviation of 50 hours. what percent of batteries have a life span that is more than 2170 hours? would it be unusual for a battery to have a life span that is more than 2170 hours? explain your reasoning. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #482973 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=482973\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the life span of a battery is normally distributed, with a mean of 2100 hours and a standard deviation of 50 hours. what percent of batteries have a life span that is more than 2170 hours? would it be unusual for a battery to have a life span that is more than 2170 hours? explain your reasoning.<BR>\n" );
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document.write( "z(2170) = (2170-2100)/50 = 70/50 = 1.4<BR>\n" );
document.write( "P(x > 2170) = P(z > 1.4) = binomcdf(1.4,100) = 0.0808<BR>\n" );
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document.write( "Not unusual.  2170 is not greater than 2 standard deviations<BR>\n" );
document.write( "above the mean.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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