document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1171770>Question 1171770</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Joe, a manager at a hamburger chain, wants to estimate a 95% confidence interval for the true mean cost<BR>\n" );
document.write( "of a hamburger in Buffalo. Joe samples 100 restaurants and discovers that the average price was $2.40 with a sample standard deviation of 80 cents. The population is known to be normal.\r<BR>\n" );
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document.write( "a. Find the standard error of the mean.<BR>\n" );
document.write( "b. Find the 95% confidence interval for the true mean price of a hamburger. Make sure you draw the<BR>\n" );
document.write( "graph. Explain in words what the confidence interval means.<BR>\n" );
document.write( "c. If Joe decides to charge $2.00 for a hamburger, would that be considered unusually low or a sale<BR>\n" );
document.write( "price? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #797141 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=797141\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> SEM is .80/sqrt(100) =$0.08.<BR>\n" );
document.write( "95% half-interval is z*sigma/sart(n)=1.96*0.80/10=0.156<BR>\n" );
document.write( "the 95% interval is ($2.244, $2.556)<BR>\n" );
document.write( "We are highly confident that the true value lies within the interval. Given that $2.00 is well below the lower limit of the interval, $2.00 sale would be an unusually low sale price. </SPAN>\n" );
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