Examples of the collision strengths. Top: original collision strengths Ω_ij(E_i) (black) for the 1404.16 Å transition in O iv (left) and the 257.77 Å transition in Fe xi (right). The colored lines correspond to the four averaging methods (Appendix A). Middle: Maxwellian Υ_ji for these transitions together with the Υs obtained using the averaged ⟨ Ω_ij(E_i) ⟩. Bottom: the same as the middle panel for κ = 2.