Table 6. HLR results for the delta ABR wave V for the right and left ears.

Bootstrapped parameters (CI, bias and SE) are only reported when the increase in step 3 was found to be significant (< 0.05) or trend-wise (<0.1). All significant improvements in step 2 and/or step 3 are marked with ^**. Trend-wise improvements are marked with *.

Right ear
	β	p	R2	CI	bias	se
Step 1
Age	0.0008	0.74	0.00
Step 2
Age	0.002	0.37	0.03**
Mean lifetime noise exposure	-0.01	0.001
Step 3
Age	0.001	0.51	0.07**	-0.0032, 0.0050	0.00005	0.002
Mean lifetime noise exposure	-0.01	0.13		-0.0273, 0.0050	-0.0001	0.008
Control/Styrene	-0.20	0.001		-0.3201, -0.0902	0.001	0.58
Control/Noise	-0.08	0.54		-0.3608, 0.2205	0.003	0.14
Left ear
	β	p	R2	CI	bias	se
Step 1
Age	0.002	0.4	0.00
Step 2
Age	0.002	0.24	0.009
Mean lifetime noise exposure	-0.005	0.05
Step 3
Age	0.002	0.31	0.02**	-0.0021, 0.0073	0.00002	0.002
Mean lifetime noise exposure	-0.004	0.44		-0.0.191, 0.0096	0.0001	0.007
Control/Styrene	-0.14	0.01		-0.2452, -0.0360	0.0002	0.05
Control/Noise	-0.06	0.56		-0.3257, 0.1907	0.001	0.13

β: Estimated coefficient of the exploratory variables that indicates changes in the auditory outcome. Note that coefficients are not standardised.

**p<0.05