document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1169693>Question 1169693</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The mean life of a battery used in a digital clock is 305 days. The lives of the batteries follow a normal distribution. The battery was recently modified to last longer. A sample of 30 of the modified batteries had a mean life of 311 days with a variance of 144 days. A hypothesis test isundertaken to determine whether the modification increased the battery life. The p  -  value of the test is equal to </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #794482 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=794482\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> this is a t-test<BR>\n" );
document.write( "t(df=29)=(x bar-mean/)s/ sqrt(n); s is sqrt of variance or 12.<BR>\n" );
document.write( "=6*sqrt(30)/12<BR>\n" );
document.write( "2.738<BR>\n" );
document.write( "One-way test<BR>\n" );
document.write( "p-value is 0.005\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
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