Table 1.

Hierarchical linear model analysis of offspring begging and growth. (Treatment is coded as 0 for C-birds and 1 for T-birds and sex is coded as 0 for females and 1 for males.)

factors	estimate	error	δ	p
(a) begging (s)
constant	9.9	1.2
treatment	4.2	1.6	7.1	<0.01
sex	7.2	1.6	19	<0.0001
age (days)	−0.4	0.1	12.3	<0.001
treatment×sex	−6.7	2.3	8.3	<0.01
treatment×age	−0.3	0.17	4.3	<0.05
sex×age	−0.7	0.17	16.6	<0.0001
treatment×sex×age	0.7	0.25	7.1	<0.01
(b) weight (g)
constant	1.32	0.23
age (days)	−0.6	0.07	69.4	<0.0001
square of age	0.2	0.01	315.7	<0.0001
cube of age	−0.007	0.00	293.9	<0.0001
treatment	−0.1	0.25	0.1	0.7
sex	−0.28	0.26	1.1	0.3
treatment×sex	0.18	0.37	0.2	0.7
treatment×age	0.06	0.02	15.9	<0.001
sex×age	0.12	0.02	54.9	<0.0001
treatment×sex×age	−0.103	0.02	19.7	<0.001