document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1156812>Question 1156812</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a) How many weeks of data must be randomly sampled to estimate the mean weekly sales of a new line of athletic footwear? We want 95% confidence that the sample mean is within $400 of the population mean, and the population standard deviation is known to be $1400.\r<BR>\n" );
document.write( "\n" );
document.write( "b) Write an interpretation. (Write answer on paper)\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #779577 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=779577\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> half-interval here its z(0.975)*sigma/sqrtI(n)<BR>\n" );
document.write( "400=1.96*1400/sqrt(n)<BR>\n" );
document.write( "400 sqrt(n)=2744<BR>\n" );
document.write( "sqrt(n)=6.86<BR>\n" );
document.write( "n=47.06 or 48 weeks<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );