document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1182743>Question 1182743</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A study of 420,065 cell phone users found that 136 of them developed cancer of the brain or nervous system. Prior to this study of cell phone​ use, the rate of such cancer was found to be 0.0316​% for those not using cell phones.\r<BR>\n" );
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document.write( "Use the sample data to construct a 95​% confidence interval estimate of the percentage of cell phone users who develop cancer of the brain or nervous system.\r<BR>\n" );
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document.write( "__% < p < __​%<BR>\n" );
document.write( "(Round to three decimal places as​ needed.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #813033 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=813033\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The 95% half-interval is z(0.975)*sqrt(p*(1-p)/n)<BR>\n" );
document.write( "=1.96*sqrt(0.000316*0.999684/420065)<BR>\n" );
document.write( "=0.0000274; add that and subtract it from 0.000323, p hat.<BR>\n" );
document.write( "so the interval is (0.000296, 0.000350)<BR>\n" );
document.write( "or (0.030%, 0.0350%)\r<BR>\n" );
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