TABLE 4.

Results of likelihood ratio tests evaluating the relationship between age and stage at hatching.

Variable	Estimate a	$\chi$ 2	p
Log(age)	4.94	1549.50	<1.0 × 10−15
Species (Ambystoma opacum)	−10.25	18.51	1.69 × 10−5
Treatment (water)	0.42	74.76	<1.0 × 10−15
Age × species	2.96	229.54	<1.0 × 10−15
Age × treatment		2.19	.14

Note: Stage was treated as the dependent variable while age, species, and treatment were treated as independent variables. Coefficients of model terms are provided for the independent variables in the best fitting model. The likelihood ratio test statistic approximates a χ ² distribution with one degree of freedom, so χ ² and associated probabilities are reported here.

^a Coefficients are provided for terms in the best fit model.