document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=189512>Question 189512</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The Academy of Orthopedic surgeons states that 90% of U.S women wear shoes that are too small for their feet. A researcher wants to be 95% confident that this proportion is within 2% of the true proportion. How large a sample is necessary? \r<BR>\n" );
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document.write( " Can you please show me how you get the answer? Thanks  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #142705 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=142705\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The Academy of Orthopedic surgeons states that 90% of U.S women wear shoes that are too small for their feet. A researcher wants to be 95% confident that this proportion is within 2% of the true proportion. How large a sample is necessary? <BR>\n" );
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document.write( "Since E = z*sqrt(pq/n)<BR>\n" );
document.write( "sqrt(n) = [z*sqrt(pq)]/E<BR>\n" );
document.write( "And n = [z/E]^2*pq<BR>\n" );
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document.write( "Your problem:<BR>\n" );
document.write( "n = [1.96/0.02]^2*(0.9*0.1) = 864.36<BR>\n" );
document.write( "Rounding up n = 865<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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