document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1091477>Question 1091477</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In the past, it has taken an express mail company an average of 2 days to deliver packages. After hiring a consulting firm, they want to know if delivery has improved. Let µ = average number of days needed to deliver a package after hiring a consulting firm. The company wants to test the following:\r<BR>\n" );
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document.write( "A sample of 25 packages yields xbar = 1.6 and s = 1.5. For &#945; = 0.05, what would you conclude? Assume the relevant population follows a normal random variable. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #705922 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=705922\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Ho=no change<BR>\n" );
document.write( "Ha=change<BR>\n" );
document.write( "alpha=0.05<BR>\n" );
document.write( "test statistic is (given normality and s an unbiased estimator of sigma) a t with df=24 <BR>\n" );
document.write( "critical value is |t| > 2.064<BR>\n" );
document.write( "calculation is t=(1.6-2)/1.5/sqrt(25)=-0.4*5/1.5=-2/1.5=-1.33<BR>\n" );
document.write( "Fail to reject Ho; insufficient evidence to conclude that delivery has improved.   </SPAN>\n" );
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