document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=322174>Question 322174</A>: <I><SPAN STYLE=\"word-break: break-all;\"> You wish to estimate, with 98% confidence, the proportion of computers that need repairs or have problems by the time they are four years old. The estimate must be accurate within 5% of the true proportion. \r<BR>\n" );
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document.write( "If no preliminary estimate is available, find the minimum sample size needed. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #230670 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=230670\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  You wish to estimate, with 98% confidence, the proportion of computers that need repairs or have problems by the time they are four years old. The estimate must be accurate within 5% of the true proportion. <BR>\n" );
document.write( "If no preliminary estimate is available, find the minimum sample size needed.<BR>\n" );
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document.write( "n = [z/E]^2*pq<BR>\n" );
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document.write( "n = [(invNorm(0.99))/0.05)^2*(1/2)^2 = 2164.7578*(1/4) = 541.18<BR>\n" );
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document.write( "n = 542 when rounded up<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "============= </SPAN>\n" );
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