a0	E(β4\y,y0) (95% CrI)	Pr(β4 > 0\y,y0)
0	0.57 (-0.03, 1.17)	0.97
0.25	0.62 (0.11, 1.18)	0.98
0.50	0.69 (0.15, 1.22)	0.99
0.75	0.78 (0.25, 1.30)	1.0
1	0.89 (0.36, 1.47)	1.0
Table 3: Posterior results for the period x group interaction term (β4) under various choices for a0.