document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=251566>Question 251566</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a study was conducted to estimate the mean amount spent on christmas gifts for a typical family having two children, a sample size 150 was taken, and the mean amount spent was $225, assuming a standard deviation equal to $50, find a 95% cinfidence interval </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #183253 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=183253\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a study was conducted to estimate the mean amount spent on christmas gifts for a typical family having two children, a sample size 150 was taken, and the mean amount spent was $225, assuming a standard deviation equal to $50, find a 95% confidence interval.<BR>\n" );
document.write( "---<BR>\n" );
document.write( "sample mean = 225<BR>\n" );
document.write( "standard error = invT(0.025 with df = 149)*50/sqrt(150) = 1.976*50/sqrt(150)<BR>\n" );
document.write( "= 8.067\r<BR>\n" );
document.write( "\n" );
document.write( "--------------<BR>\n" );
document.write( "95% CI: 225-8.067 < u < 225+8.067<BR>\n" );
document.write( "95% CI: 216.933 < u < 233.067<BR>\n" );
document.write( "=====================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );