document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1157182>Question 1157182</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a sample of 100 Republicans, 72 favored the president’s anti  -  drug program; while in a sample of 150 Democrats, 84 favored his program.<BR>\n" );
document.write( "a.	Is there a significant difference in the proportions of the Democrats and the Republicans who favored the president’s anti-drug?\r<BR>\n" );
document.write( "\n" );
document.write( "b.	Estimate the difference at 95% confidence level. <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 #780010 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=780010\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a two sample proportion test<BR>\n" );
document.write( "z=(p hat r-p hat d)/ sqrt ( p1*(1-p1)/n1) + (p2(1-p2)/n2))<BR>\n" );
document.write( "reject Ho if the 95% CI for the difference between the mean doesn't contain 0.<BR>\n" );
document.write( "the difference between the means is 0.16<BR>\n" );
document.write( "the SE is sqrt(.72*.28/100 + .56*.44/150)=0.0604<BR>\n" );
document.write( "z is 1.96<BR>\n" );
document.write( "half-interval is 0.1184, round to 0.12<BR>\n" );
document.write( "the 95% CI for the difference between the two proportion means is (0.04, 0.28). <BR>\n" );
document.write( "That is one answer. The meaning is that because zero is not in the interval, we are highly confident the true difference is not zero. <BR>\n" );
document.write( "You can do this as a hypothesis test rejecting the null if |z|>1.96 for a two way test. It is. <BR>\n" );
document.write( "On the calculator want STAT TESTS 9 2 Samp Z interval <BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );