document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1193669>Question 1193669</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Each of two groups consists of 100 patients who have leukaemia. A new drug is given to the first group but not to the second (the control group). It is found that in the first group 60 people have remission for 2 years; but only 40 in the second group. Find 95% CI.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #825719 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=825719\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> two sample proportion 95% half-interval is z*SE<BR>\n" );
document.write( "SE:  start with group 1 SE which is sqrt(0.6*0.4/100) or 0.0490, and group 2 SE which is the same<BR>\n" );
document.write( "the SE is sqrt(0.0490^2+0.0490^2)=0.0693<BR>\n" );
document.write( "z*SE=1.96*0.0693=0.1358<BR>\n" );
document.write( "the actual 95%CI is the difference +/- SE which is (0.0642, 0.3358). We are looking at the difference in proportion of survival between 1 and 2.<BR>\n" );
document.write( "This is consistent with the highly significant difference.<BR>\n" );
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