The influence of the observation error distribution on the orbits of 22 asteroids potentially hazardous for the Earth has been studied. First, we computed the mean errors of orbit parameters on the assumption of the linear connection of them with observation errors and then we compared obtained estimates with those resulting from the assumption of the nonlinearity of this connection. Secondly, we correlate orbital parameters and their errors obtained by the method of the least modulus with those obtained by the least-squares method. The general conclusion is that the dispersion ellipsoids calculated on the assumption of nonlinearity are more plausible, and the orbits and estimates of their errors calculated by the least modulus method are more robust compared to those obtained by the least-squares method.