def get_delta_TI_or_MBAR(TI_or_MBAR_estimate, k_b_T):
    """ Return the change in free energy and standard deviation for the MBAR and TI estimates.

    """
    delta = TI_or_MBAR_estimate.delta_f_.iloc[0, -1] * k_b_T
    std_delta = TI_or_MBAR_estimate.d_delta_f_.iloc[0, -1] * k_b_T
    return delta, std_delta