document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=221022>Question 221022</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A standard placement test has a mean of 105 and a standard deviation of &#963; = 13. Determine the minimum sample size if we want to be 99% certain that we are within 3 points of the true mean </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #165873 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=165873\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A standard placement test has a mean of 105 and a standard deviation of &#963; = 13. Determine the minimum sample size if we want to be 99% certain that we are within 3 points of the true mean<BR>\n" );
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document.write( "n = [z*sig/E]^2<BR>\n" );
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document.write( "invNorm(0.005) = -2.576<BR>\n" );
document.write( "n = [2.576*13/3]^2<BR>\n" );
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document.write( "n = 124.6<BR>\n" );
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document.write( "Round up to n= 125<BR>\n" );
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