Table 2.

Results of forward stepwise regression analysis of response variables with more than one significant regressor. Data were measured in adult female G. holbrooki collected from eight Florida springs.

Response variable	Step	r2	p-value	Regressors	Partial r
Ovary weight	1	0.86	< 0.0001	Body weight	0.93
	2	0.91	< 0.0001	Body weight	0.92
				Stage	0.57
	3	0.97	< 0.0001	Body weight	0.69
				Stage	0.82
				Embryo number	0.82
Embryo numbera	1	0.64	< 0.0001	Standard length	0.80
	2	0.77	< 0.0001	Standard length	0.86
				Embryo dry weighta	−0.61
Embryo wet weighta, b	1	0.66	< 0.0001	Stage	0.81

^aAnalyses involving embryo number or embryo weight include embryos at stage 3 or greater; staging based on Haynes (1995).

^bEmbryo wet weight was positively correlated with both stage (shown) and maternal body weight (r² = 0.21, p < 0.0001). However, when both are included in a stepwise regression model for embryo wet weight, only stage enters the model.