document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=296597>Question 296597</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In 2004, ACT, INC. reported that 74% of 1644 randomly selected college freshman returned to college the next year. Estimate the national freshman-to-sophomore retention rate.<BR>\n" );
document.write( "a) Check that the assumptions and conditions are met for inference on proportions.<BR>\n" );
document.write( "b) Construct a 98% confidence interval<BR>\n" );
document.write( "c) Interpret your interval<BR>\n" );
document.write( "d) Explain what \"98% confidence\" means in this context. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #213687 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=213687\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In 2004, ACT, INC. reported that 74% of 1644 randomly selected college freshman returned to college the next year. Estimate the national freshman-to-sophomore retention rate.<BR>\n" );
document.write( "a) Check that the assumptions and conditions are met for inference on proportions.<BR>\n" );
document.write( "b) Construct a 98% confidence interval<BR>\n" );
document.write( "p-hat = 0.74<BR>\n" );
document.write( "ME = 2.3263*sqrt(0.74*0.26/1644) = 0.0252<BR>\n" );
document.write( "-<BR>\n" );
document.write( "98% CI: 0.74-0.0252 < p < 0.74+0.0252<BR>\n" );
document.write( "98% CI: 0.7148 < p < 0.7652<BR>\n" );
document.write( "-------------------------------------<BR>\n" );
document.write( "c) Interpret your interval<BR>\n" );
document.write( "We have 98% confidence that the proportion of freshman who return as<BR>\n" );
document.write( "sophomores is between 0.7148 and 0.7652<BR>\n" );
document.write( "-----------------------------------------------<BR>\n" );
document.write( "d) Explain what \"98% confidence\" means in this context.<BR>\n" );
document.write( "See \"c\"<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" );