  In the paper the Bayesian and the least squares methods of quantum state
tomography are compared for a single qubit. The quality of the estimates are
compared by computer simulation when the true state is either mixed or pure.
The fidelity and the Hilbert-Schmidt distance are used to quantify the error.
  It was found that in the regime of low measurement number the Bayesian method
outperforms the least squares estimation. Both methods are quite sensitive to
the degree of mixedness of the state to be estimated, that is, their
performance can be quite bad near pure states.
