document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=866641>Question 866641</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A researcher wishes to estimate the number of households with two computers. How large a sample is needed in order to be 95% confident that the sample proportion will not differ from the true proportion by more than 5%? A previous study indicates that the proportion of households with 2 computers is 21%.<BR>\n" );
document.write( "A) 5<BR>\n" );
document.write( "B) 180 <BR>\n" );
document.write( "C) 323<BR>\n" );
document.write( "D) 255 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #522418 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=522418\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A researcher wishes to estimate the number of households with two computers. How large a sample is needed in order to be 95% confident that the sample proportion will not differ from the true proportion by more than 5%? A previous study indicates that the proportion of households with 2 computers is 21%.<BR>\n" );
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document.write( "E = zsqrt(pq/n)<BR>\n" );
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document.write( "n = [z/E]^2*pq<BR>\n" );
document.write( "n = [1.96/0.05]^2*0.21*0.79 = 255 when rounded up<BR>\n" );
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document.write( "A) 5<BR>\n" );
document.write( "B) 180 <BR>\n" );
document.write( "C) 323<BR>\n" );
document.write( "D) 255<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );