pub fn qn(x: &[f64]) -> Result<f64>Expand description
Q_n scale estimator with Gaussian consistency constant and the
finite-sample corrections used by robustbase::Qn (Croux & Rousseeuw 1992,
updated constants). Q_n = d_n · 2.21914 · {|x_i − x_j|; i<j}_(k) with
k = C(h,2), h = ⌊n/2⌋+1. Returns 0 for n < 2.