document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1159559>Question 1159559</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A random sample of 9 health maintenance organizations (HMOs) was selected. For each HMO, the co-payment (in dollars) for a doctor's office visit was recorded. The results are as follows:<BR>\n" );
document.write( "10, 5, 12, 6, 12, 11, 6, 12, 10<BR>\n" );
document.write( "Under the assumption that co-payment amounts are normally distributed, find a  90% confidence interval for the mean co-payment amount in dollars. Then complete the table below.\r<BR>\n" );
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document.write( "Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #782619 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=782619\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You need the mean, the sd, the sample size.<BR>\n" );
document.write( "the mean is 9.333<BR>\n" );
document.write( "the sd for the sample is 2.872<BR>\n" );
document.write( "the sample size is 9\r<BR>\n" );
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document.write( "90%CI is mean +/- t(0.95, df=9) s/sqrt(n)<BR>\n" );
document.write( "the half-interval is 1.86*2.872/3=1.78\r<BR>\n" );
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document.write( "the 90% CI is ($7.55, $11.11)\r<BR>\n" );
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