  We propose a new method for the calculation of the statistical properties, as
e.g. the entropy, of unknown generators of symbolic sequences. The probability
distribution p(k) of the elements k of a population can be approximated by the
frequencies f(k) of a sample provided the sample is long enough so that each
element k occurs many times. Our method yields an approximation if this
precondition does not hold. For a given f(k) we recalculate the Zipf-ordered
probability distribution by optimization of the parameters of a guessed
distribution. We demonstrate that our method yields reliable results.
