A particular additive is claimed to increase the fuel efficiency of hybrid vehicles. Eight hybrid cars are used to determine if there is a difference in fuel efficiency (l/100km) with and without the additive. The appropriate nonparametric method to use for these data is the
A) Kruskal-Wallis test.
B) Kendall's tau test.
C) Wilcoxon signed-rank test.
D) Wilcoxon rank-sum test.
E) Spearman's rho test.

Question

Quizplus · Accepted Answer

The appropriate nonparametric test for comparing the fuel efficiency of hybrid vehicles with and without the additive is the Wilcoxon signed-rank test, as it is a paired test where each car is tested twice, once with and once without the additive. The Kruskal-Wallis test is used for comparing three or more independent samples, Kendall's tau and Spearman's rho tests are used for measuring the strength of association between two variables, and the Wilcoxon rank-sum test is used for comparing two independent samples.

A Particular Additive Is Claimed to Increase the Fuel Efficiency