Kruskal-Wallis H-test

Non-parametric comparisons of location for three or more samples include the Kruskal-Wallis H-test. Here, the two data sets can be unequal in size, but again the underlying distributions are assumed to be similar. 

The data were not normally distributed. Thus, we used a Kruskal-Wallis H-test on ranks to determine if significant differences existed in the amount of time male voles self-groomed when they were exposed to the different odor stimuli (H = 45.63, df = 5, P < 0.001). Male meadow voles spent more time self-grooming when they were exposed to odors of female meadow voles as compared to the odors of male meadow voles, male and female prairie voles, vanilla, and clean cotton (Dunn s test, p < 0.05 for all comparisons. Figure 1), Male meadow voles, however, spent similar amounts of time self-grooming in response to odors of male meadow voles, male and female prairie voles, vanilla, and clean cotton (Dunn s test, P > 0.05 for all comparisons Figure 1). 

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