document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1076071>Question 1076071</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A local bus services company wants to estimate the average amount of fuel used to travel between Lusaka and Solwezi.  A sample of 50 trips was taken and the sample mean amount of was 500 litres. If the population standard deviation is 200 litres construct the 95% confidence interval within which the population mean amount must lie. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #690832 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=690832\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The standard error is sigma/sqrt(n)=200/sqrt(50)=28.3 l<BR>\n" );
document.write( "The 95% CI is mean +/- 1.96*SE; we don't use the t here, because we are given the sd of the population.<BR>\n" );
document.write( "That is mean +/- (1.96*28.3)=500+/-55.4 liters or (444.6, 555.4) </SPAN>\n" );
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