document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1121207>Question 1121207</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The manager of the Marua Shopping Mall in Windhoek claims that visitors to this mall spend<BR>\n" );
document.write( "always more than 90 minutes in the mall on any occasion. To test this claim, the chairman of the<BR>\n" );
document.write( "Namibian Chamber of Commerce and Industry (NCCI) commissioned a study which found that, from<BR>\n" );
document.write( "a random sample of 25 recent visitors to this mall, the average visiting time was 95.5 minutes, with a<BR>\n" );
document.write( "standard deviation of 15 minutes.<BR>\n" );
document.write( "2.2.1) Formulate a suitable null and alternative hypothesis for this situation. (2)<BR>\n" );
document.write( "2.2.2) Which test statistic ( z or t ) is most appropriate to use? & Why? (3)<BR>\n" );
document.write( "2.2.3) Compute the sample statistic (3)<BR>\n" );
document.write( "2.2.4) Formulate the decision rule by using &#945; = 10 % (3)<BR>\n" );
document.write( "2.2.5) What conclusion can the chairman of the Namibian Chamber of Commerce and Industry<BR>\n" );
document.write( "(NCCI) draw from the findings? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #737017 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=737017\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Ho: average visiting time <=90 minutes<BR>\n" );
document.write( "Ha: average visiting time >90 minutes.  Want to reject Ho if there is a true difference.  One way test, since we know which direction the difference will be if significant.<BR>\n" );
document.write( "alpha=0.10<BR>\n" );
document.write( "One sample t-test 0.90, df=24 since using sd of sample as unbiased estimator of sd of population.<BR>\n" );
document.write( "critical value t>1.711<BR>\n" );
document.write( "t=(x bar-mean)/s/sqrt(n)=(95.5-90)/15/sqrt (25)<BR>\n" );
document.write( "=5.5*5/15=1.83<BR>\n" );
document.write( "Can reject Ho at the 10% level and say that the average visiting time is > 90 minutes.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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