document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1157326>Question 1157326</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A political candidate has asked you to conduct a poll to determine what percentage of people support her.\r<BR>\n" );
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document.write( "If the candidate only wants a 8% margin of error at a 95% confidence level, what size of sample is needed?\r<BR>\n" );
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document.write( "Give your answer in whole people. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #780241 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=780241\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 8% error means z*SE=0.08; z(0.975)=1.96<BR>\n" );
document.write( "SE=sqrt(.5*.5/n), because the probability  of people supporting is not known.  When that happens, use 0.5 as it gives the most conservative estimate.  The largest product of two fractions that add to 1 occurs when both are 1/2.\r<BR>\n" );
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document.write( "so 1.96* sqrt(.25/n)=0.08<BR>\n" );
document.write( "square both sides<BR>\n" );
document.write( "3.84*.25=0.0064*n, moving the n across<BR>\n" );
document.write( "n=150 people  </SPAN>\n" );
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