document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1175012>Question 1175012</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1. You measure 29 textbooks' weights, and find they have a mean weight of 34 ounces. Assume the population standard deviation is 2.8 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight.<BR>\n" );
document.write( "Give your answers as decimals, to two places\r<BR>\n" );
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document.write( "2. If n=28,¯x(x-bar)=36, and s=17, construct a confidence interval at a 90% confidence level. Assume the data came from a normally distributed population.<BR>\n" );
document.write( "Give your answers to one decimal place. \r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #800617 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=800617\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 95% half-interval is z*sigma/sqrt(n)=1.96*2.8/sqrt(29)=1.02 books<BR>\n" );
document.write( "95% CI is (32.98, 35.02)  oz<BR>\n" );
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document.write( "the half-interval is z*17/sqrt(28) where z=1.645, so it is 5.28<BR>\n" );
document.write( "using the mean from the first part (not clear)<BR>\n" );
document.write( "(28.7, 39.3) oz<BR>\n" );
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