als-statistics/lib/descriptive/z-outliers.js

Modular JS statistics toolkit for Node.js and the browser: descriptive stats, correlations (Pearson/Spearman/Kendall), t-tests & ANOVA (Student/Welch), reliability (Cronbach’s alpha), regression (linear/logistic), clustering (DBSCAN/HDBSCAN), and table/co

function outliersZScore({ zScores, values }, threshold = 3, twoFactors = true, below = false) {
  const outliers = [], indexes = [], zs = [];
  for (let i = 0; i < zScores.length; i++) {
    const zi = zScores[i];
    const z = twoFactors ? Math.abs(zi) : zi;
    const isOutlier = twoFactors
      ? (z > threshold) && (!below || zi < -threshold) // если below=true — только «нижние»
      : (below ? (zi < -threshold) : (zi > threshold));
    if (!isOutlier) continue;
    outliers.push(values[i]); indexes.push(i); zs.push(zi);
  }
  return { values: outliers, indexes, zScores: zs };
}

export default outliersZScore