document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1120954>Question 1120954</A>: <I><SPAN STYLE=\"word-break: break-all;\"> People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 95&#8203;% &#8203;confidence? Initial survey results indicate that sigmaequals 13.8 books.\r<BR>\n" );
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document.write( "A 95 % confidence level requires _____ subjects.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #736665 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=736665\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> sigma means we can use z and +/- 1.96.<BR>\n" );
document.write( "the SE is z*sigma/sqrt(n), and that equals 1 book, the error.<BR>\n" );
document.write( "1.96*13.8/sqrt(n)=1<BR>\n" );
document.write( "square both sides and multiply everything by n\r<BR>\n" );
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document.write( "3.8416*190.44=1<BR>\n" );
document.write( "n=731.59 or 732 subjects </SPAN>\n" );
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