The order of permutation of 0,1,2,3 is [0,1,2,3], [0,1,3,2], [0,2,1,3], [0,2,3,1], [0,3,1,2], [0,3,2,1], [1,0,2,3], [1,0,3,2], [1,2,0,3], ...

Permutation tests are non-parametric statistical tests that assess the significance of an observed effect by comparing it to the distribution of effects generated by randomly shuffling the data.