def METHOD_NAME(sim_data):
    """
    Objective function for PEC to optimize. This function takes in the simulation data,
    a 3D array of shape (num_trials, num_estimates, num_outcome_vars), and returns a
    scalar value that is the reward rate.
    """
    return np.mean(sim_data[:, :, 0][:] / sim_data[:, :, 1][:])