what dose the "iteration" mean in SPM nonparametric analysis code

[Xlcandy]

Hi, Todd

I would like to conduct some nonparametric analysis like nonparam hotelling paired t-test and nonparam paired t-test etc. But I found that all the spm code there have a word "iterations", and if I change the number behind it, the result will also change. I would like to ask that, what dose the "iteration" mean? and what is the appropriate range of the number behind it for hotelling test and paired t-test?

Thank you all the time. :)

[0todd0000]

An iteration is a random permutation of the observations' labels. Generally: it should be 10,000 or 100,000, or as big as possible in order to achieve stable results.

Please find relevant discussions in issues #63, #116, and #187.

Here is a wonderful paper describing permutation-based inference: Nichols, T. E., & Holmes, A. P. (2002). Nonparametric permutation tests for functional neuroimaging: a primer with examples. Human Brain Mapping, 15(1), 1-25. https://onlinelibrary.wiley.com/doi/abs/10.1002/hbm.1058

Please feel free to continue the discussion here if any questions remain.

[Xlcandy]

Oh many thanks!