document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=409758>Question 409758</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that the lifespan of a particular type of lightbulb is normally distributed with a mean of 1000 hours and a variance of 8100 hours. Determine the probability that a randomly selected lightbulb will last for 800 hours or less? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #288324 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=288324\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose that the lifespan of a particular type of lightbulb is normally distributed with a mean of 1000 hours and a variance of 8100 hours. Determine the probability that a randomly selected lightbulb will last for 800 hours or less?<BR>\n" );
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document.write( "z(800) = (800-1000)/(8100) = -200/8100 = -2/81<BR>\n" );
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document.write( "P(x <= 800) = P(x < -2/81) = normalcdf(-100,-2/81) = 0.4902<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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