document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1178141>Question 1178141</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A recent study examined the association between high blood pressure and increased risk of death from cardiovascular disease. There were 2676 men with low blood pressure and 3338 men with high blood pressure. In the low-blood-pressure group, 21 men died from cardiovascular disease; in the high-blood-pressure group, 55 died.\r<BR>\n" );
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document.write( "Compute the 95% confidence interval for the difference in<BR>\n" );
document.write( "Proportions.\r<BR>\n" );
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document.write( "Do the study data confirm that death rates are higher among men with high blood pressure? \r<BR>\n" );
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document.write( "State hypotheses, carry out a significance test, and give your conclusions.<BR>\n" );
document.write( "(Thank you) (Please) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #807334 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=807334\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> p1=low BP=0.00784<BR>\n" );
document.write( "p2=high BP=0.01648<BR>\n" );
document.write( "the difference is 0.00863<BR>\n" );
document.write( "the 95% half-interval  is z* diff (means)*SE, the general form.<BR>\n" );
document.write( "the SE is sqrt[((0.00784*0.99216/2676+(.01648*0.98312/3338))]=0.000002907+0.000004854=0.0028<BR>\n" );
document.write( "Here, it is 1.96*0.0028=0.0055<BR>\n" );
document.write( "the interval is (0.0031, 0.0141), and since the interval does not contain 0, there is a difference between the two proportions.<BR>\n" );
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document.write( "the p-value will be 0.0126<BR>\n" );
document.write( "It is worth doing a couple by brute force to get an idea how the test works, but these are extremely easy to put in a calculator or program.\r<BR>\n" );
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