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Wilcoxon and REML Questions

Hi All, 

I've had 2 questions from a customer trying to do some work in JMP. These are:

1. Can a Wilcoxon / Kruskal Wallace test be performed on Ordinal data directly in JMP? I appreciate it can be treated as continuous dataset to achieve the same result just wondered if it can be done without this step!
2. When generating a mixed model and using REML, is it possible to impose a correlation structure i.e. autoregressive on it?

Thanks in advance

Stuart

Re: Wilcoxon and REML Questions

Hi @Stuart_Little ,

Not sure about 1. 

As for 2. I think you would need the Mixed Model personality in JMP Pro for specifying correlation structures. @jiancao is the expert on this stuff.

Hope that helps in some way?!

Phil

Re: Wilcoxon and REML Questions

For #2, yes,  there is an AR(1) -autoregressive of order  1- for within-subject covariances.  It assumes a correlation between two adjacent measurements with geometric progression.

https://www.jmp.com/support/help/en/16.2/#page/jmp/repeated-covariance-structures.shtml#ww1273585

It is one of my favorites since it can be used together with an additional random effect to account for  between-subject variability.