A large company is deciding between transportation methods for shipping its finished goods. Since the possibility of labour stoppages is a concern, a manager studied Data Set 20 in Appendix B for annual person-days lost through work stoppages in different modes of transportation. For each of the transportation modes shown in the table below, she independently selected a random sample of 14 years' data. (The table shows annual person days lost, in thousands.) At the 0.05 level of significance, test the claim that the four populations of annual person-days lost have the same mean. Basedon the results, does it appear that the four modes are equally reliable, in terms of possible loss of service due to labour stoppage? Does any single category seem to be particularly reliable in this regard? Do we have enough information, from these results, to decide on the best mode of transportation to use? Explain.

For Exercises 5-7, use the data shown in the margin (based on the Financial Post list of top 500 companies for 1998). Revenues, assets, and numbers of employees are compared for samples of companies from three industry groups: wholesale distributors (1), food production and sales industries (2), and conglomerates (3). Revenues and assets are in millions of dollars.

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ır Rail Water Truck 14 n, = 14 60.805 x,-58.036 2 71.558 12.631 x, = 19.896 워 = 33.131 s 63.303 5 = 13.627