Table 1. Multiple regression results for larval production per barnacle based on the natural population surveys.

Source of variation	R2	df	SS	F	P	VC*	Percent of total
In(number of larvae produced per barnacle)
Basal diameter	0.50	1	24.359	56.376	<0.0001	–	–
Height: basal diameter		1	6.718	15.547	0.0001	–	–
Site		2	0.698	0.141	0.876	–0.055	–11.424
Zone		1	0.043	0.025	0.887	–	–
Site × zone		2	5.454	6.311	0.002	0.106	21.952
Error		130	56.171	–	–	0.432	89.472
In(number of larvae per barnacle)
Basal diameter	0.44	1	43.155	92.318	<0.0001	–	–
Height: basal diameter		1	7.197	15.396	0.0001	–	–
Error		135	63.107	–	–	–	–

SS, Sum of Squares.

^*VC, variance components, which were calculated by using the traditional estimated mean squares approach because of the presence of negative variance components