document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=324664>Question 324664</A>: <I><SPAN STYLE=\"word-break: break-all;\"> To test the null hypothesis that the average lifetime for a particular brand of bulb is 775 hours versus the alternative that the average lifetime is different from 775 hours, a sample of 120 bulbs is used. If the standard deviation is 65 hours and &#945; is equal to 0.01, what values for xbar will result in rejection of the null hypothesis (show all work). <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #232415 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=232415\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> To test the null hypothesis that the average lifetime for a particular brand of bulb is 775 hours versus the alternative that the average lifetime is different from 775 hours, a sample of 120 bulbs is used. If the standard deviation is 65 hours and &#945; is equal to 0.01, what values for xbar will result in rejection of the null hypothesis.<BR>\n" );
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document.write( "Ho: u = 775<BR>\n" );
document.write( "Ha: u is not 775<BR>\n" );
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document.write( "Critical value for 2-tail t-test with alpha=1% and df=119 = +-2.6178<BR>\n" );
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document.write( "xbar = 2.6178*65+775 = 945.16<BR>\n" );
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document.write( "xbar = -2.6178*65+775 = 604.84<BR>\n" );
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document.write( "Any xbar< 604.84 or greater than 945.16 will result in rejection of Ho.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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