document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=586714>Question 586714</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A new fluorescent light to replace incandescent bulbs has come on the market. The box says life of 8,000 hours with a standard deviation of 750 hours. A random sample of 50 light bulbs is taken. Let Xbar be the mean of the sample.<BR>\n" );
document.write( "A. What is the probability that Xbar is >or equal to 7900?<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #373856 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=373856\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A new fluorescent light to replace incandescent bulbs has come on the market. The box says life of 8,000 hours with a standard deviation of 750 hours. A random sample of 50 light bulbs is taken. Let Xbar be the mean of the sample.<BR>\n" );
document.write( "A. What is the probability that Xbar is >or equal to 7900?<BR>\n" );
document.write( "----<BR>\n" );
document.write( "z(7900) = (7900-8000)/[750/sqrt(50)] = -0.9428<BR>\n" );
document.write( "P(x-bar >= 7900) = P(z>-0.9428) = 0.8271<BR>\n" );
document.write( "=============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );