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Thread: Post Hoc analysis for non-parametric analysis in Minitab: HELP

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    Post Hoc analysis for non-parametric analysis in Minitab: HELP




    Greetings

    I wish to be able to use post hoc analysis on my non-parametric analysis on my data. I am currently using Krustal Wallis (as I have 5 sets of data that I wish to compare). As this will only give me a p-value and a z-value which informs me if the data is significantly different or not and the general ball park that the data sets are inn respectively. However, I wish to know which of my datasets are significantly different or not but theres no options to do so in minitab. Have I overlooked something?

    PS: Basically what I want something like the ANOVA - Fisher pairwise comparisons.

    Please advice.

    Marius

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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    Minitab's nonparametric tests do not currently provide post hoc tests. Your only apparent options are to see whether you can use a 1-way ANOVA, or subset the data, perform the pairwise tests on the sub-setted data and adjust your p-values manually.

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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    I typically use pairwise Wilcoxon Rank Sum tests after a significant omnibus test such as the Kruskal Wallis. Not a Minitab user, so no help there.
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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    Quote Originally Posted by hlsmith View Post
    I typically use pairwise Wilcoxon Rank Sum tests after a significant omnibus test such as the Kruskal Wallis. Not a Minitab user, so no help there.
    If they subset the data, to allow pairwise comparisons, Minitab has a 2-sample option for Mann-Whitney. Unfortunately, their Wilcoxon is a 1-sample test, so unless you have paired data and perform the test on the differences, you are out of luck.

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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    hi,:
    maybe you can use the aligned rank transform . I do not know for sure, but I suppose the transorm could be implemented manually in Minitab and the resulting transformed data analysed with normal ANOVA.

    regards

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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    I recall using a minitab macro that provides the facility to run Dunn's posthoc test. Maybe it is still in the Minitab's macros repository. Try and google a little.

    Best
    Gm

    EDIT:
    I googled a little for you: http://support.minitab.com/en-us/min...macros/krusmc/
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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP

    Thanks everyone for replies, really appreciate it! Yeah it seems to be quite a big limitation with minitab so I just got a SPSS trial instead and used the built inn post hoc analysis "Pairwise comparisons" in the KW test in the "new" independent sample option whenver the p-value < 0.05. That makes sense right? It provides this pairwise comparison where each combination of the various groups has an assosiated p-value which quickly showes me which group are statistically differnet.

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    Re: Post Hoc analysis for non-parametric analysis in Minitab: HELP


    Ah cheers gianmarco, thats pretty much spot on. I googled for ages and didnt find anything! I did turn to SPSS for this but I will definitly keep this in mind for future reference.

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