document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1159553>Question 1159553</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An existing inventory for a test measuring self-esteem indicates that the scores have a standard deviation of 12. A psychologist gave the self-esteem test to a random sample of 60 individuals, and their mean score was 60 . Construct a 90% confidence interval for the true mean of all test scores. Then complete the table below.<BR>\n" );
document.write( "Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.\r<BR>\n" );
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document.write( "What is the lower limit of the 90% confidence interval?	<BR>\n" );
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document.write( "What is the upper limit of the 90% confidence interval?	<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 #782627 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=782627\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Because the sd is known, this is a z-interval<BR>\n" );
document.write( "The interval is the mean+/-z(0.95)*sigma/sqrt(n)<BR>\n" );
document.write( "the half-interval or the margin of error is 1.645*12/sqrt(60)<BR>\n" );
document.write( "=2.548 or 2.55<BR>\n" );
document.write( "(57.45, 62.55) or (57.5, 62.4), the asymmetry being due to rounding. </SPAN>\n" );
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