hummingbird-me/hummingbird

export default function wilsonScore(pos, n) {
  if (n === 0) {
    return 0;
  }

  //z=1.96 corresponds to confidence=0.95
  //z=2.17 corresponds to confidence=0.97
  var z = 1.96;
  var phat = 1.0 * pos / n;

  return (phat + z * z / (2 * n) - z * Math.sqrt((phat * (1 - phat) + z * z / (4 * n)) / n)) / (1 + z * z / n);
}