def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types):
        """
        See :meth:`superclass method
        <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
        for spec of input and result values.
        """
        # extracting dictionary of coefficients (for soil amplification)
        # specific to required intensity measure type
        C_SR = self.COEFFS_SOIL_RESPONSE[imt]

        # compute median PGA on rock (in g), needed to compute non-linear site
        # amplification
        C = self.COEFFS_AC10[PGA()]
        pga4nl = np.exp(
            self._compute_mean(C, rup.mag, dists.rjb, rup.rake)) * 1e-2 / g

        # compute full mean value by adding site amplification terms
        # (but avoiding recomputing mean on rock for PGA)
        if imt == PGA():
            mean = (np.log(pga4nl) +
                    self._get_site_amplification_linear(sites.vs30, C_SR) +
                    self._get_site_amplification_non_linear(sites.vs30, pga4nl,
                                                            C_SR))
        else:
            C = self.COEFFS_AC10[imt]
            mean = (self._compute_mean(C, rup.mag, dists.rjb, rup.rake) +
                    self._get_site_amplification_linear(sites.vs30, C_SR) +
                    self._get_site_amplification_non_linear(sites.vs30, pga4nl,
                                                            C_SR))

        # convert from cm/s**2 to g for SA (PGA is already computed in g)
        if imt.name == "SA":
            mean = np.log(np.exp(mean) * 1e-2 / g)

        stddevs = self._get_stddevs(C, stddev_types, num_sites=len(sites.vs30))

        return mean, stddevs
See :meth:`superclass method
        <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
        for spec of input and result values.