Delta Air Lines wants to determine if the number of no-shows for flights originating from Detroit is higher than from Minneapolis. A sample of 20 flights from each city is taken and the number of no-shows is determined for each flight. Which nonparametric test would you use to determine whether the number of no-shows is greater in Detroit?
A)Wald-Wolfowitz one-sample runs test
B)Wilcoxon signed-rank test
C)Wilcoxon rank sum (Mann-Whitney) test
D)Kruskal-Wallis test

Question

Quizplus · Accepted Answer

The Wilcoxon rank sum test (also known as the Mann-Whitney U test) is used to compare the distribution of two independent samples. In this case, the number of no-shows from Detroit and Minneapolis are two independent samples, and we want to compare their distributions to see if one has a higher median than the other. The Wald-Wolfowitz test and Wilcoxon signed-rank test are both one-sample tests and not appropriate for comparing two independent samples. The Kruskal-Wallis test is used to compare more than two independent samples.

Delta Air Lines Wants to Determine If the Number of No-Shows