def _set_default_stats_options(stats_options):
    """Define some default summary statistics to display in estimation table."""
    if stats_options is None:
        stats_options = {
            "n_obs": "Observations",
            "rsquared": "R$^2$",
            "rsquared_adj": "Adj. R$^2$",
            "resid_std_err": "Residual Std. Error",
            "fvalue": "F Statistic",
        }
    else:
        if not isinstance(stats_options, dict):
            raise TypeError(
                f"""stats_options can be of types dict or NoneType.
            Not: {type(stats_options)}."""
            )
    return stats_options