document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1139925>Question 1139925</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a survey, the planning value for the population proportions P* = 0.5. How large a sample should be taken to provide a 90% confidence interval with a margin of error of 0.07?<BR>\n" );
document.write( "Please keep two decimal places of your answer. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #760439 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=760439\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> margin of error is z*sqrt(p*(1-p)/n)=0.07 and z(0.95)=1.645 for a CI of 90%\r<BR>\n" );
document.write( "\n" );
document.write( "square both sides and 1.645^2*0.25/n=0.0049<BR>\n" );
document.write( "2.706025*0.25=0.0049n<BR>\n" );
document.write( "n=138.06 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );