The manager of the Marua Shopping Mall in Windhoek claims that visitors to this

mall spend always more than 90 minutes in the mall on any occasion. To test this

claim, the chairman of the Namibian Chamber of Commerce and Industry (NCCI)

commissioned a study which found that, from a random sample of 25 recent visitors

to this mall, the average visiting time was 95.5 minutes, with a standard deviation of

15 minutes.

3.1)Formulate a suitable null and alternative hypothesis for this situation.

3.2) Which test statistic ( z or t ) is most appropriate to use ? & Why ?

3.3) Compute the sample statistic

3.4) Formulate the decision rule by using = 10 %

3.5) What conclusion can the chairman of the Namibian Chamber of Commerce and

Industry (NCCI) draw from the findings?