document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1162463>Question 1162463</A>: <I><SPAN STYLE=\"word-break: break-all;\"> To estimate the average time it takes to assemble a certain computer component the industrial engineer at an electronics firm timed 49 technicians in the performance of this task, getting a mean of 12.00 minutes and a standard deviation of 1.90 minute. (i) What can we say with 95% confidence about the maximum error if X = 12.00 is used as a point estimate of the actual average time required to do the job? (ii) Use the given data to construct a 99% confidence interval for the true average time it takes to assemble  the computer components.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #787850 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=787850\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> this is a 95% t-interval with x bar 12, s=1.9 min, and n=49<BR>\n" );
document.write( "t 0.975, df=48=2.01<BR>\n" );
document.write( "half-interval is 2.01*s/sqrt(n)=2.01*1.90/7=0.545<BR>\n" );
document.write( "the 95% CI is (11.45, 12.55) min<BR>\n" );
document.write( "for 99%, t=2.68<BR>\n" );
document.write( "half-interval is 2.68*1.9/7=0.727 or 0.73<BR>\n" );
document.write( "99% interval is (11.27, 12.73) min </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );