Probability p_Q that an observed giant is a quasar giant under the unification model. Under this model, giants generated by AGN with quasar appearance (quasar giants) have inclination angles θ ≤ θ_max or θ ≥ 180° −θ_max and giants generated by AGN without quasar appearance (non-quasar giants) have intermediate θ. As long as quasar giants and non-quasar giants are subject to the same selection effects, these selection effects do not affect p_Q. Instead, in such case, p_Q only depends on the maximum quasar inclination angle θ_max and the tail index ξ.