I just performed a Kruskal-Wallis Test to compare movements between 4 groups of frogs and now I am going through the pairwise Dunn's comparisons. I'm trying to report my results in a paper. How do I interpret the z-scores that JMP gives for Dunn's Test?
For example, for one of the comparisons the first level (let's call Group A) is compared to the second level (let's call Group B). JMP gives me a Z score of -3.64. My interpretation of this is that Group A is 3.64 units less than Group B. So I'm wondering, when I go to report my results in the text, would it be incorrect for me to make a statement like "Group B frogs moved greater distances (mean: 42 meters +/- 0.5; Z = -3.64, P = <0.0001) than Group A (mean: 2 meters +/- 0.2)? Would I need to remove the negative symbol before the Z score because JMP was using Group A as the reference rather than Group B? Or would the Z score be something different altogether if Group B were the reference?
I know I could just state that Group B frogs moved shorter distances than Group A frogs and not have to worry about it, but I'm trying to be concise and Group C and Group D also moved greater distances than Group A so instead of using a lot of text going back and forth, I'd like to list the stats consecutively like this:
"Pairwise comparisons indicated that Group B, Group C, and Group D frogs exhibited significantly greater daily distances (Group B: mean = 43.38 ± 13.07 m/day, z = -5.52, P = <0.0001; Group C: mean = 11.30 ± 2.17 m/day; z = -4.46, P = <0.0001; Group mean = 10.20 ± 2.11 m/day, z = -4.34, P = <0.0001) than Group A frogs (mean = 0.24 ± 0.13 m/day; Fig. 5b)."