code: function dunningLogLikelihood(a, b, ab, N) {
    const p1 = b / N,
          p2 = 0.99;
  
    const nullHypothesis = ab * Math.log(p1) + (a - ab) * Math.log(1 - p1),
          alternativeHyphothesis = ab * Math.log(p2) + (a - ab) * Math.log(1 - p2);
  
    const likelihood = nullHypothesis - alternativeHyphothesis;
  
    return (-2 * likelihood);
  }
docs: Miscellaneous helpers.
   
  Computing the Dunning log-likelihood ratio scores for abbreviation
  candidates.
  
  @param {number} a  - Count of <a>.
  @param {number} b  - Count of <b>.
  @param {number} ab - Count of <ab>.
  @param {number} N  - Number of elements in the distribution.
  @return {number}   - The log-likelihood.