Table 5.

Summary of hierarchical linear model for quality with working memory capacity (WM) as a predictor.

Fixed effect	Coeff.	Std. error	T-ratio	d.f	P-value
STEP 1
For Intercept
Intercept	0.446	0.019	22.759	27	<0.001
WM	−0.005	0.032	−0.144	27	0.887
For Slope
Fidelity index	1.127	0.032	29.444	27	<0.001
WM	−0.056	0.065	−0.868	27	0.393
STEP 2
For Intercept
Intercept	0.461	0.043	10.817	26	<0.001
WM	−0.004	0.031	−0.129	26	0.899
PTA	−0.0007	0.001	−0.642	26	0.526
For Slope
Fidelity index	1.014	0.107	9.480	26	<0.001
WM	−0.058	0.063	−0.918	26	0.367
PTA	0.003	0.003	1.154	26	0.259
STEP 3
For Intercept
Intercept	0.249	0.111	2.246	25	0.034
WM	0.011	0.031	0.360	25	0.721
PTA	−0.001	0.001	−0.572	25	0.572
Age	0.003	0.002	1.886	25	0.071
For Slope
Fidelity index	1.164	0.295	3.944	25	0.001
WM	−0.069	0.063	−1.082	25	0.290
PTA	0.003	0.003	1.135	25	0.268
Age	−0.002	0.003	−0.572	25	0.572

Amount of hearing loss (PTA) is average of thresholds at 1, 2, 3, and 4 kHz in the test ear.