Left: likelihood distribution functions from the De Filippis et al. (2005) and re-selected Constitution SN Ia pairs for two parameterizations: η( z) = 1 + η ₀ z and η( z) = 1 + η ₀ z/(1 + z). Right: likelihood distribution functions from the Bonamente et al. (2006) and Constitution SN Ia pairs for the same parameterizations. The top and bottom panels correspond to the cases without and with the errors of SNe Ia, respectively.