document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1181286>Question 1181286</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In order to estimate the average age of onset of a certain type of disease a researcher collects a sample of 15 people with the disease and produces the following 95% confidence interval (83.9219, 90.6782). Find a 99% confidence interval for the average age based on the same data set </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #813728 by </B><A HREF=/tutors/aboutme.mpl?userid=robertb><B>robertb(5830)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=robertb><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=robertb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=813728\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The sample mean is the average of the endpoints of the C.I., thus <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X-bar+=+%2883.9219+%2B+90.6782%29%2F2+=+87.3 ALIGN=MIDDLE  ALT=\"X-bar+=+%2883.9219+%2B+90.6782%29%2F2+=+87.3\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "Now from the initial given, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5B0.975%5D%2A%28s%2Fsqrt%2815%29%29+=++90.6782+-+87.3+=+3.3782 ALIGN=MIDDLE  ALT=\"t%5B0.975%5D%2A%28s%2Fsqrt%2815%29%29+=++90.6782+-+87.3+=+3.3782\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "===> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2.145%2A%28s%2Fsqrt%2815%29%29+=+3.3782 ALIGN=MIDDLE  ALT=\"2.145%2A%28s%2Fsqrt%2815%29%29+=+3.3782\"   DISABLED_style= \"max-width:90%; height:auto;\" >  ==> s = 6.1.\r<BR>\n" );
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document.write( "Then the new 99% C.I. will be <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28X-bar%29+%2B-+t%5B0.995%5D%2A%28s%2Fsqrt%2815%29%29+=+87.3+%2B-+2.977%2A%286.1%2Fsqrt%2815%29%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > = (82.6112, 91.9888).\r<BR>\n" );
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document.write( "The t-probabilities were gotten from https://stattrek.com/online-calculator/t-distribution.aspx. </SPAN>\n" );
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