public T getQuantileLowerBound(final double fraction) {
    return getQuantile(max(0, fraction - Util.getNormalizedRankError(k_, false)));
  }
public T getQuantileLowerBound ( final double fraction ) { return getQuantile ( max ( 0 , fraction - Util . getNormalizedRankError ( k_ , false ) ) ) ; }
Gets the lower bound of the value interval in which the true quantile of the given rank
exists with a confidence of at least 99%.
@param fraction the given normalized rank as a fraction
@return the lower bound of the value interval in which the true quantile of the given rank
exists with a confidence of at least 99%. Returns NaN if the sketch is empty.