Function percentile

src/utils/mathUtils.ts:12–19

(sorted: number[], p: number)

 * @returns The p-th percentile value, or 0 if array is empty
 */
export function percentile(sorted: number[], p: number): number {
  if (sorted.length === 0) return 0;
  const idx = (p / 100) * (sorted.length - 1);
  const lower = Math.floor(idx);
  const upper = Math.ceil(idx);
  if (lower === upper) return sorted[lower];
  return sorted[lower] * (upper - idx) + sorted[upper] * (idx - lower);
}

/**
 * Calculate the median of an array.