  In the frameworks of hypothesis of practical constancy of the neutron
resonance number in small fixed intervals of neutron energy, their most
probable value was determined for nucleus mass region 230<A<244 from
approximation of the reduced neutron widths by superposition of two or four
independent distributions. This was done under assumption that a set of the
measured neutron amplitudes can correspond to one or to superposition of some
normal distributions with non-zero average and dispersion differing from
reduced neutron width. The main result of the analysis: the mean spacing and
neutron strength function values can be determined only with unknown
systematical uncertainty whose magnitude is determined by unknown precision of
the Porter-Thomas hypothesis correspondence to concrete experimental sets of
resonances and unknown experimental mean neutron widths.
