Table 2.

Summary of hierarchical multiple regression analyses for intention to quit

Predictors	β	t	df	R 2	Δ R 2
Step 1
Nicotine dependence	−0.20	−2.92*
Causal attribution	0.25	3.52*
Perceived illness severity	−0.08	−1.02
Event-related fear	0.21	2.66*	181	0.138**
Step 2
Nicotine dependence	−0.21	−2.92*
Causal attribution	0.27	3.53*
Perceived illness severity	−0.08	−0.99
Event-related fear	0.21	2.65*
Causal attribution × perceived illness severity	−0.04	−0.46
Causal attribution × event-related fear	0.05	0.64	179	0.140**	0.002

Degrees of freedom of residuals are reported

^*p<0.01;

^**p<0.001