document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1182430>Question 1182430</A>: <I><SPAN STYLE=\"word-break: break-all;\"> For a sample of 16 Philips light bulbs, the mean lifetime is 1250 hours with a standard deviation of 250 hours.  For sample of 12 Liwanag light bulbs, the mean lifetime is 1400 hours with standard deviation of 300 hours.  Use a 0.01 level of significance to test whether or not there is a significant difference between the average lifetimes of the two brands of light bulbs.\r<BR>\n" );
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document.write( "Thanks in advance! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #812470 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=812470\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> this is a 2-way 2-sample t-test <BR>\n" );
document.write( "Ho: P=L<BR>\n" );
document.write( "Ha: P NE L<BR>\n" );
document.write( "alpha=0.01<BR>\n" );
document.write( "test is a t (0.99,df=26), reject for |t| > 2.779<BR>\n" );
document.write( "t=(diff means)/ sqrt ((s1^2/n1)+(s2^2/n2))<BR>\n" );
document.write( "=-150/ sqrt ((250^2/16)+(300^2/12)); denominator is sqrt(11406.25)<BR>\n" );
document.write( "=-150/106.8<BR>\n" );
document.write( "=-1.40<BR>\n" );
document.write( "insufficient evidence to reject Ho<BR>\n" );
document.write( "p-value = 0.17 </SPAN>\n" );
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