  The $\pi$N forward scattering data are analyzed using an expansion method,
where the invariant amplitudes are represented by expansions satisfying the
forward dispersion relations. The experimental errors of the data are taken
into account through the covariance matrix of the coefficients of the
expansions in a careful error analysis. From the results, some coefficients,
$c_{n0}^\pm$, of the subthreshold expansions have been calculated with proper
error bars.
