document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=279758>Question 279758</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A manufacturer receives an order for fluorscent light bulbs. The order requires that the bulbs have a mean life span of 550 hours. The manufacturer selects a random sample of 25 fluorescent light bulbs and finds that they have a mean life span of 545 hours with a standard deviation of 15 hours. Is the manufacturer making acceptable light bulbs? Defend your answer. use a 95% confidence level. Assume the data is normally distributed.\r<BR>\n" );
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document.write( "Please show work. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #203354 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=203354\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  A manufacturer receives an order for fluorscent light bulbs. <BR>\n" );
document.write( "The order requires that the bulbs have a mean life span of 550 hours. <BR>\n" );
document.write( "The manufacturer selects a random sample of 25 fluorescent light bulbs and finds that they have a mean life span of 545 hours with a standard deviation of 15 hours. Is the manufacturer making acceptable light bulbs? Defend your answer. use a 95% confidence level. Assume the data is normally distributed.<BR>\n" );
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document.write( "sample mean = 545<BR>\n" );
document.write( "standard error = E = invT(0.975.24)*15/sqrt(25) = 6.1917<BR>\n" );
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document.write( "95% CI: 545-6.1917 < u < 545+6.1917<BR>\n" );
document.write( "95% CI: 538.81 < u < 551.19<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. <BR>\n" );
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