document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=138296>Question 138296</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Confidence interval for the population mean: Use of the t distribution <BR>\n" );
document.write( "A toy manufacturer wants to see how long, on average, a new toy captures children's attention. He tests 20 children selected at random and finds that their mean attention span is 31 minutes with a standard deviation of 6 minutes. If we assume that attention spans are normally distributed, find a 90 confidence interval for the mean attention span of children playing with this new toy. Then complete the table below. <BR>\n" );
document.write( "Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. \r<BR>\n" );
document.write( "\n" );
document.write( "(If necessary, consult a list of formulas.) <BR>\n" );
document.write( "What is the lower limit of the confidence interval<BR>\n" );
document.write( "What is the higher limit of the confience interval <BR>\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 #100998 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=100998\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A toy manufacturer wants to see how long, on average, a new toy captures children's attention. He tests 20 children selected at random and finds that their mean attention span is 31 minutes with a standard deviation of 6 minutes. If we assume that attention spans are normally distributed, find a 90 confidence interval for the mean attention span of children playing with this new toy. Then complete the table below. <BR>\n" );
document.write( "Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. <BR>\n" );
document.write( "(If necessary, consult a list of formulas.) <BR>\n" );
document.write( "What is the lower limit of the confidence interval: 28.68<BR>\n" );
document.write( "What is the higher limit of the confience interval: 33.32<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "Numbers are the result of running a T-Interval program on a Ti calculator<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" );