document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=986137>Question 986137</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Southside Hospital in Bay Shore, New York, commonly conducts stress tests to study the heart muscle after a person has a heart attack.  Members of the diagnostic imaging department conducted a quality improvement project with the objective of reducing the turnaround time for stress tests.  Turnaround time is defined as the time from when a test is ordered to when the radiologist signs off on the test results.  Initially, the mean turnaround time for a stress test was 68 hours.  After incorporating changes into the stress-test process, the quality improvement team collected a sample of 50 turnaround times.  In this sample, the mean turnaround time was 32 hours, with a standard deviation of 9 hours.<BR>\n" );
document.write( "a) if you test the null hypothesis at the 0.01 level of significance, is there evidence that the new process has reduced turnaround time?<BR>\n" );
document.write( "b)interpret the meaning of the p-value in this problem<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #606963 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=606963\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Ho=mean is 68 hours<BR>\n" );
document.write( "Ha=mean is not 68 hours<BR>\n" );
document.write( "alpha=0.01<BR>\n" );
document.write( "test statistic is t df=49<BR>\n" );
document.write( "critical value |t|>2.68<BR>\n" );
document.write( "calculation  t= (value-68)/s/sqrt (n)<BR>\n" );
document.write( "t= (32-68)*sqrt(50)/9<BR>\n" );
document.write( "t=-28.3<BR>\n" );
document.write( "This is highly significant, which makes intuitive sense, given that that the sample +4 sds would be needed to reach the first mean.  There is very strong evidence to say that the change could not have occurred by chance.<BR>\n" );
document.write( "The likelihood of this result's occurring by chance is well less than one in a million.  <BR>\n" );
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