code: @Override
      protected final double inverseF(Random u) throws MathException {
          final double uvalue = (u.nextGaussian() + 1) / 2.;
          return inverseF(uvalue);
      }
docs: Replies the x according to the value of the inverted
  cummulative distribution function {@code F<sup>-1</sup>(u)}
  where {@code u = U(0, 1)}.
  
  @param u is the uniform random variable generator {@code U(0, 1)}.
  @return {@code F<sup>-1</sup>(u)}
  @throws MathException in case {@code F<sup>-1</sup>(u)} could not be computed