document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=451261>Question 451261</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the sample size needed to be able to estimate the mean dollars that each card holder will spend each month. It would like to be within plus or minus $25 of the true mean with a 98% confidence level. It would like to be within plus or minus $25 of the true mean with a 98% confidence level. The standard deviation is thought to be $400. How many card holders should be sampled? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #310459 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=310459\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> What is the sample size needed to be able to estimate the mean dollars that each card holder will spend each month. It would like to be within plus or minus $25 of the true mean with a 98% confidence level.  The standard deviation is thought to be $400. How many card holders should be sampled?<BR>\n" );
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document.write( "n = [z*s/E]^2<BR>\n" );
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document.write( "n = [2.3263*400/25]^2 = 347 when rounded up<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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