document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1141129>Question 1141129</A>: <I><SPAN STYLE=\"word-break: break-all;\"> You wish to estimate with 90% confidence, the proportion of U.S. adults who made one or more emergency room visits in the past year.  How large of a sample will you need if your estimate is to be within 3% of the population proportion? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #761697 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=761697\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Largest number or most conservative estimate assumes proportion is 0.5<BR>\n" );
document.write( "the half-interval is z*sqrt(p*(1-p)/n)=0.03, the error.<BR>\n" );
document.write( "square both sides and multiply through by n<BR>\n" );
document.write( "1.645^2*0.25=0.0009n<BR>\n" );
document.write( "n=751.67 or 752 people </SPAN>\n" );
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