document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1133246>Question 1133246</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A researcher wishes to estimate the proportion of adults who have​ high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.04 with 90​% confidence if<BR>\n" );
document.write( "​(a) she uses a previous estimate of 0.58​?<BR>\n" );
document.write( "​(b) she does not use any prior​ estimates? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #750706 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=750706\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Margin of Error(ME) = 0.04<BR>\n" );
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document.write( "critical statistic(z) for a 90% confidence level is 1.645<BR>\n" );
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document.write( "when standard deviation is not known, we use<BR>\n" );
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document.write( "sample size n = p*(1-p)*(z/ME)^2, where p is the proportion<BR>\n" );
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document.write( "a) n = 0.58 * (1-0.58)*(1.645/0.04)^2 = 411.9923<BR>\n" );
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document.write( "sample size is 412<BR>\n" );
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document.write( "b) p is not known, so use p = 0.50<BR>\n" );
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document.write( "n = 0.50 * (1-0.50)*(1.645/0.04)^2 = 422.8164<BR>\n" );
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document.write( "sample size is 423 <BR>\n" );
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