document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=140268>Question 140268</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In order to test whether marathon races are bad for health, a researcher took a random sample of 400 runners who participated in the New York half marathon, and found that 13% of them got sick in the two-week period after the marathon. In a second sample of 400 runners who did not participate in the marathon, only 3% were sick in the same two week period. What would be the null hypothesis? Find a 90% confidence interval for the percentage of New York half marathon runners who got sick in the two weeks after the race.\r<BR>\n" );
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document.write( "PLS pls help, I am only a student in long distance education and need help to solve exam problems. This is from my question paper </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #102168 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=102168\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In order to test whether marathon races are bad for health, a researcher took a random sample of 400 runners who participated in the New York half marathon, and found that 13% of them got sick in the two-week period after the marathon. In a second sample of 400 runners who did not participate in the marathon, only 3% were sick in the same two week period. What would be the null hypothesis? Find a 90% confidence interval for the percentage of New York half marathon runners who got sick in the two weeks after the race. <BR>\n" );
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document.write( "1st sample:<BR>\n" );
document.write( "n1=400<BR>\n" );
document.write( "p-hat = 0.13<BR>\n" );
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document.write( "2nd sample:<BR>\n" );
document.write( "n2=400<BR>\n" );
document.write( "p-hat = 0.03<BR>\n" );
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document.write( "Ho: p1 - p2 = 0<BR>\n" );
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document.write( "Confidence Interval<BR>\n" );
document.write( "p1-hat - p2-hat = 0.10<BR>\n" );
document.write( "E = 1.645*sqrt[(0.13*0.87/400) + (0.03*0.97)/400)] = 0.031016<BR>\n" );
document.write( "90% CI: 0.1-0.031016 < p < 0.1 + 0.31016<BR>\n" );
document.write( "= 0.68984 < p < 1.31016\r<BR>\n" );
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document.write( "===============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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