Levels of (a) |$q_{U_{i}D_{i}}$| with respect to |$q_{U_{i}I_{i}}$| and levels of (b) |$q_{U_{i}I_{i}}$| with respect to ϕ, all within 95 per cent confidence intervals. The levels of |$q_{U_{i}I_{i}}$| and ϕ are depicted on the x-axes, while the corresponding levels of |$q_{U_{i}D_{i}}$| and |$q_{U_{i}I_{i}}$| are represented on the y-axes.