Refer to Exercise 8.23.
a. Use a nonparametric procedure to compare the mean reliability of the seven plants.
b. Even though the necessary conditions are not satisfied, use the Tukeyâ€™s W procedure to group the seven nuclear power plants based on their mean reliability.
c. Compare your results in part (b) to the groupings obtained in part (a).
In a 1996 article published in Technometrics, (Martz, Kvan, Abramson, 1996), the authors discuss the reliability of nuclear-power-plant emergency generators. To control the risk of damage to the nuclear core during accidents at nuclear plants, the reliability of emergency diesel generators (EDGs) to start on demand must be maintained at a very high level. At each nuclear power plant, there are a number of such generators. An overall measure of reliability is obtained by counting the number of times the EDGs successfully work when needed. The table here provides the number of successful demands for implementation of an EDG between each subsequent failure in an EDG for all the EDGs at each of seven nuclear power plants. A regulatory agency wants to determine if there is a difference in the reliabilities of the seven nuclear power plants.
a. Do the conditions necessary for conducting the AOV F test appear to be satisfied by these data?
b. Because the data are counts of the number of successes for the EDGs, the Poisson model may be an alternative to the normal-based analysis. Apply a transformation to the data, and then apply the AOV F test to the transformed data.
c. As a second alternative analysis that has fewer restrictions, answer the agencyâ€™s question by applying the Kruskalâ€“Wallis test to the reliability data.
d. Compare your conclusions to parts (a)â€“(c). Which of the three procedures provides the conclusion about which you feel most confident?