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    Which statistical test shoud I use?




    I have concentrations of one metal in two organs of a snail kidney and foot (n=10). What statistical test should I use to check if the difference is significant between them?

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    Re: Which statistical test shoud I use?

    Are the data paired or independent? If you had 10 snails, and had paired kidney and foot data for each snail, use a paired t-test. If the data are independent use a 2-sample t-test. If the data are not normal, there are non-parametric equivalents to these.

    This assumes that you meant differences between organs. If you meant differences between snails, that is a different question.

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    Re: Which statistical test shoud I use?

    Thank you. Yes, I meant differences between organs. My data is non-parametric.

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    Re: Which statistical test shoud I use?

    How do you know that it is non-parametric? Does it fail a normality test? If the data are paired, test the differences for normality, not the groups.

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    Re: Which statistical test shoud I use?

    Shapiro Wilk Sig. was smaller than 0,05; so my data is non-parametric. Am I wrong? I have serious problems with my data analysis. ;/

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    Re: Which statistical test shoud I use?

    If your data are paired (you still haven't stated) calculate the differences and use the 1-sample Wilcoxon test. If not paired, use Mann-Whitney test.

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    Re: Which statistical test shoud I use?

    In the first post there seems to be four factors (or five) and a mixed model because of within individual (foot kidney) effects and between individual effects.

    I guess that the amount of metal will have many values close to zero and a few larger, so that it is a skewed distribution. Taking logs could possibly solve that.

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    Re: Which statistical test shoud I use?


    I didn't see that thread. That description is completely different from the one in this thread.

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