document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1170281>Question 1170281</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a survey, 30 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $49 and standard deviation of $7. Construct a confidence interval at a 80% confidence level.\r<BR>\n" );
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document.write( "Give your answers to one decimal place. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #795334 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=795334\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> half-interval is t(0.90, df=29)*s/sqrt(n)<BR>\n" );
document.write( "=1.311*7/sqrt(30)<BR>\n" );
document.write( "=1.675<BR>\n" );
document.write( "CI is mean+/- half-interval or<BR>\n" );
document.write( "($47.325, $50.675) Or ($49.3, $50.7)  </SPAN>\n" );
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