Refer to the Marine Technology (Jan. 1995) study of major ocean oil spills by tanker vessels, Exercise 2.85. The spillage amounts (thousands of metric tons) and cause of accident for 48 tankers are saved in the OILSPILL file. (Note: Delete the two tankers with oil spills of unknown causes.) Conduct an analysis of variance (at α = .01) to compare the mean spillage amounts for the four accident types: (1) collision, (2) grounding, (3) fire/explosion, and (4) hull failure. Interpret your results.

Data from Exercise 2.85

Owing to several major ocean oil spills by tank vessels, Congress passed the 1990 Oil Pollution Act, which requires all tankers to be designed with thicker hulls. Further improvements in the structural design of a tank vessel have been proposed since then, each with the objective of reducing the likelihood of an oil spill and decreasing the amount of outflow in the event of a hull puncture. To aid in this development, Marine Technology (Jan. 1995) reported on the spillage amount (in thousands of metric tons) and cause of puncture for 50 recent major oil spills from tankers and carriers.