code: function(q, lowerTail, logp) {
          return lowerTail ? logp ? log1p(-q) : 1 - q
                           : logp ? Math.log(q) : q;
        }
docs: /*
  Given a upper tail probability value, it "adjusts" it to
  requested lowerTail and logp settings.
  
  It expects q in the range (0, 1).
  Use `adjustLower` for q = 0 or 1.