document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=241409>Question 241409</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can anybody help me with this question?  The question is:<BR>\n" );
document.write( "Develop a 90 percent confidence interval for the population mean.  Interpret the results.<BR>\n" );
document.write( "The Greater Pittsburgh Area Chamber of Commerce wants to estimate the mean time workers who are employed in the downtown area spend getting to work.  A sample of the 15 workers reveals the following number of minutes spent traveling.<BR>\n" );
document.write( "29	38	38	33	38	21	45	34<BR>\n" );
document.write( "40	37	37	42	30	29	35<BR>\n" );
document.write( "Develop a 98 percent confidence interval for the population mean.  Interpret the results.<BR>\n" );
document.write( "Thank you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #176790 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=176790\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Develop a 90 percent confidence interval for the population mean. Interpret the results.<BR>\n" );
document.write( "The Greater Pittsburgh Area Chamber of Commerce wants to estimate the mean time workers who are employed in the downtown area spend getting to work. A sample of the 15 workers reveals the following number of minutes spent traveling.<BR>\n" );
document.write( "29 38 38 33 38 21 45 34<BR>\n" );
document.write( "40 37 37 42 30 29 35<BR>\n" );
document.write( "------------<BR>\n" );
document.write( "sample mean = 35.067<BR>\n" );
document.write( "sample std = 6.017<BR>\n" );
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document.write( "standard error = z*s/sqrt(n)<BR>\n" );
document.write( "standard error = 1.645*6.017/sqrt(15) = 2.556<BR>\n" );
document.write( "-------------------------------------------------------<BR>\n" );
document.write( "90% CI: 35.067-2.556 < u < 35.067+2.556<BR>\n" );
document.write( "90% CI: 32.511 u < 37.62<BR>\n" );
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document.write( "Develop a 98 percent confidence interval for the population mean. Interpret the results.<BR>\n" );
document.write( "Use the z-value for 98%: z = 2.3263<BR>\n" );
document.write( "sample mean is the same as above<BR>\n" );
document.write( "standard error = 2.3263*6.017/sqrt(15)=3.614<BR>\n" );
document.write( "---<BR>\n" );
document.write( "98% CI: 35.067 - 3.614 < u < 35.067 + 3.614<BR>\n" );
document.write( "98% CI: 31.45 < u < 38.68<BR>\n" );
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document.write( "Meaning: We have 98% confidence the population mean is between<BR>\n" );
document.write( "31.45 and 38.68<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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