document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1058596>Question 1058596</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A population is estimated to have a standard deviation of 15. We want to estimate the population mean within 3, with a 90% level of confidence. (Use  z Distribution Table.)<BR>\n" );
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document.write( "How large a sample is required? (Round the z-values to 2 decimal places. Round up your answer to the next whole number.)<BR>\n" );
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document.write( "  Sample required is	.   </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #673675 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=673675\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The CI has to be 3.<BR>\n" );
document.write( "3=z*sigma/sqrt(n);z=1.65, sd=15<BR>\n" );
document.write( "3 sqrt(n)=1.65*15=24.75<BR>\n" );
document.write( "sqrt (n)=8.25<BR>\n" );
document.write( "n=68.06, rounds up to 69. </SPAN>\n" );
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