document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1100116>Question 1100116</A>: <I><SPAN STYLE=\"word-break: break-all;\"> You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately &#963;=46.2. You would like to be 90% confident that your estimate is within 3 of the true population mean. How large of a sample size is required?<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 #714591 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=714591\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 90% CI half interval is 1.645+/-sigma/sqrt(n)<BR>\n" );
document.write( "3=1.645*46.2/sqrt(n)<BR>\n" );
document.write( "square both sides<BR>\n" );
document.write( "9=5775.85/n<BR>\n" );
document.write( "n=641.76 or 642<BR>\n" );
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