document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=970729>Question 970729</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a random sample of 30 people who rode a roller coaster one day, the mean wait time is 46.7 minutes with a standard deviation of 9.2 minutes. In a random sample of 50 people who rode a Ferris wheel the same day, the mean wait time is 13.3 minutes with a standard deviation of 1.9 minutes. Construct a 99% confidence interval for the difference between the mean wait times of everyone who rode both rides.\r<BR>\n" );
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document.write( "A. (31.7, 35.1)<BR>\n" );
document.write( "B. (30.5, 36.3)<BR>\n" );
document.write( "C. (29, 37.8)<BR>\n" );
document.write( "D. (28.7, 38.1) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #593402 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=593402\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  In a random sample of 30 people who rode a roller coaster one day, the mean wait time is 46.7 minutes with a standard deviation of 9.2 minutes. In a random sample of 50 people who rode a Ferris wheel the same day, the mean wait time is 13.3 minutes with a standard deviation of 1.9 minutes. Construct a 99% confidence interval for the difference between the mean wait times of everyone who rode both rides.<BR>\n" );
document.write( "sample mean difference:: 46.7-13.3 = 33.4<BR>\n" );
document.write( "ME = 2.5857*sqrt[(9.2^2/30)+(1.9^2/50)] = 4.4<BR>\n" );
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document.write( "99% CI:: 33.4-4.4 ; 33.4+4.4<BR>\n" );
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document.write( "Ans: C<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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document.write( "A. (31.7, 35.1): <BR>\n" );
document.write( "B. (30.5, 36.3):: <BR>\n" );
document.write( "C. (29, 37.8)<BR>\n" );
document.write( "D. (28.7, 38.1) </SPAN>\n" );
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