Generate null distribution for rank sum statistic — null_dist • CMRSS

Computes the randomization null distribution of a single rank sum statistic under complete randomization.

Usage

null_dist(
  n,
  m,
  method.list = NULL,
  score = NULL,
  nperm = 10^5,
  Z.perm = NULL,
  chunk_size = 1000
)

Arguments

n: Total number of units.
m: Number of treated units.
method.list: A list specifying the scoring method.
score: Optional pre-computed score vector.
nperm: Number of permutations.
Z.perm: Optional pre-computed permutation matrix.
chunk_size: Integer chunk size used to generate permutations when Z.perm is NULL. Smaller values use less memory.

Value

A numeric vector of length nperm containing the null distribution.

Examples

set.seed(1)
score <- rank_score(20, list(name = "Wilcoxon", scale = FALSE))
nd <- null_dist(n = 20, m = 12, score = score, nperm = 500)
quantile(nd, c(0.5, 0.95))
#>    50%    95% 
#> 127.00 148.05