document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=575691>Question 575691</A>: <I><SPAN STYLE=\"word-break: break-all;\"> . An electrical firm manufactures light bulbs that have a length of life that is normally distributed with mean equal to 800 hours and standard deviation of 40 hours. Find the probability that a bulb burns between 778 and 834 hours.                                                  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #369585 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=369585\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> An electrical firm manufactures light bulbs that have a length of life that is normally distributed with mean equal to 800 hours and standard deviation of 40 hours. Find the probability that a bulb burns between 778 and 834.<BR>\n" );
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document.write( "Using z-calculations:<BR>\n" );
document.write( "z(778) = (778-800)/40 = -0.55<BR>\n" );
document.write( "z(834) = (834-800)/40 = 0.85<BR>\n" );
document.write( "P(778<= x <=834) = P(-0.55<= z <=0.85) = normalcdf(-0.55,0.85) = 0.5112<BR>\n" );
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document.write( "Using a TI-84:<BR>\n" );
document.write( "normalcdf(778,834,800,40) = 0.5112<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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