adaptive_perm_test: Adaptive permutation test
In floatofmath/adaperm: Permutation tests for adaptive designs

Perform an adaptive permutation test

1 2	adaptive_perm_test(x1, x2, g1, g2, stat, B, alpha = 0.025, x3 = NULL, g3 = NULL)

`x1`	First stage observations
`x2`	Second stage observations
`g1`	First stage treatment assignments
`g2`	Second stage treatment assignments (see Details)
`stat`	Function that computes the test statistic
`B`	Number of draws from the permutation distribution to use
`alpha`	Significance level of the test
`x3`	Third stage observations (e.g. sample size increase)
`g3`	Third stage treatment allocations (e.g. sample size increase)