document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=135397>Question 135397</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Here is another one I need help with. Thanks in Advance.\r<BR>\n" );
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document.write( "1. If I am surveying the constituents for my favorite candidate ... and I wish to be 95% confident of the estimate I develop for the proportion of the constituents that favor my candidate and i want the error to be within 2% (0.02) of the actual population proportion<BR>\n" );
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document.write( ">> how many folks do there need to be in my sample ??\r<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 #99195 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=99195\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If I am surveying the constituents for my favorite candidate ... and I wish to be 95% confident of the estimate I develop for the proportion of the constituents that favor my candidate and i want the error to be within 2% (0.02) of the actual population proportion\r<BR>\n" );
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document.write( ">> how many folks do there need to be in my sample ?? <BR>\n" );
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document.write( "Formula: E = z*sqrt(pq/n)<BR>\n" );
document.write( "sqrt(n) = z*(sqrt(pq)}/E<BR>\n" );
document.write( "n = [z/E}^2*pq<BR>\n" );
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document.write( "z-score for 95^ confidence = 1.96<BR>\n" );
document.write( "Since p is not given, avoid bias by letting p=1/2=q<BR>\n" );
document.write( "E is given as 0.02<BR>\n" );
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document.write( "n = [1.96/0.02]^2(1/4)<BR>\n" );
document.write( "n = 9604*(1/4)<BR>\n" );
document.write( "n = 2401 (desired sample size)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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