Adding 4OHIF exposure to the model did not result in an improvement of goodness-of-fit of this relationship.
Karaca-Mandic, Norton and Dowd [34] explained that the significance of interaction terms indicates improvement of the goodness of fit of the model, while it does not indicate a significance of a cross-partial effect, and the sign of interaction terms is not the sign of a cross-partial effect.
Statistical comparison of the direct indirect effects model (Equation 2) and the classical animal model (Equation 1), showed a significant improvement of the goodness of fit for both lines and for all body regions (Table 2; all P-values < 0.001 except P = 0.13 for belly in line W1), providing evidence for indirect genetic effects on FCS for almost all body regions.
This can take a value of between 0 and 1 and is a marker of the improvement in goodness of fit of the current model over a model containing just the intercept term.
Among these datasets, reductions in −2×log-likelihood from more than 1 to more than 16 were seen, and for most of them improvement in goodness-of-fit was equally marked.
Apart from the improvement in goodness of fit, the results of the MZIP models show promise toward the goal of obtaining more accurate estimates by accounting for excess zeros in correlated count data.
The choice of this split was unequivocal as the improvement in goodness-of-fit (both from drop in deviance and misclassification standpoints) from splitting on size at this point was substantially larger than for any of the other explanatory variables.
Quadratic and linear quadratic models of cumulative silica exposure did not result in an improvement in goodness of fit.
The contributions of the non-market sector and utility maximisation to improvement in goodness-of-fit tests are analysed further in Heckman and Sedlacek (1990).
However, the spline curve indicating the relationship between PA dose and lower risk of ACM and CVD risk neither detected these levels nor had significant improvement in goodness of fit compared with linearity.
