Table 4. PVM-susceptibility values across generations fit with additive-dominance model.

Traits	Individual scaling test		Joint scaling test
	C ± s.e.	t test	m ± s.e.	± s.e.	± s.e.	χ2 (1)	P
LVLd7	−0.09±0.38	N S	4.85±0.06	1.92±0.06	0.67±0.11	0.06	0.8
ΔBWd0–d7	2.81±0.61	P<0.05	1.75±0.14	1.37±0.17	0.94±0.24	21.5	<0.001
ΔEBd6–d7	−0.02±0.061	N S	0.05±0.01	0.05±0.01	0.09±0.02	0.11	0.74

LVL^d7, day 7 pi lung viral load; ΔBW^d0–d7, body weight loss as measured 7 days pi; ΔEB^d6–d7, change in expiratory balance between days 6 and 7 pi. Scaling tests according to Mather and Jinks, 1982. See Materials & Methods section for key.