Following are the data from Exercise 16.48 on running times, in minutes, for random samples of films in four rating groups.

a. Use the Kruskal-Wallis test to decide, at the 1% significance level, whether the data provide sufficient evidence to conclude that a difference exists in mean running times among films in the four rating groups.
b. The hypothesis test in part (a) was done in Exercise 16.48 by using the one-way ANOVA test. The assumption there is that running times in the four rating groups are normally distributed and have equal standard deviations. Presuming that to be true, why is performing a Kruskal-Wallis test to compare the means permissible? In this case, is use of the one-way ANOVA test or the Kruskal- Wallis test better? Explain your answers.

1s or 1.5* 2* or 2.5 3* or 3.5*4* 75 95 84 86 58 85 97 70 105 119 87 95 101 89 35 93 103 117 86 126 100 119 101 97