Two-sample test, based on permutations and Wellner's Rayleigh-style T-statistic (Wellner, 1979, Example 1a).

Assumes small sample sizes. Deterministically generates all choose(nx + ny, nx) reassignments of the data to the two groups. For large sample sizes, see rayWellnerInference.

Usage

wellner_exact_inference_ray(xs, ys)

Arguments

xs

A list of rays.

ys

A list of rays.

Value

A real number, between 0 and 1 inclusive. The fraction of tests in which T exceeds the original T for the data. You can interpret this as a p-value for the null hypothesis that the two populations are identical (not just that their means are identical). In other words, small values of p indicate that the distinction between the two populations is meaningful.