Table 7.

Comparison of the goodness of fit for four different mixed models (models 7 to 9 and the unstructured model), as fitted to CIMMYT maize stress trials.

Model	Deviance	DF	Δ Deviance	Δ DF	P	AIC
Model 7	1077.9	1678	–	–	–	4170
Model 8	838.4	1671	239.5	7	<0.001	3944
Model 9	619.9	1667	218.5	4	<0.001	3736
Unstructured	548.7	1644	71.2	23	<0.001	3708

The columns “Δ deviance” and “Δ DF” indicate the differences in deviance and number of degrees of freedom between the current and the preceding model in the list. The associated P values correspond to a Chi-square distribution with Δ DF degrees of freedom.