Table 4.

The parameters of the final model of signal-to-noise ratio obtained by calculating the mixed effects of sound pressure level, exposure time, and frequency

Model parameter	Estimate	Standard deviation	Degrees of freedom	t-Coefficient	P-value	95% confidence interval
						Lower bound	Upper bound
Intercept	28.64	2.95	19	9.70	0.001	22.47	34.82
SPL	−0.081	0.032	18	−2.51	0.022	−0.15	−0.013
Time	−0.34	0.11	18	−2.99	0.008	−0.58	−0.10
Frequency	−0.0002	0.0001	83	−1.36	0.175	−0.00052	9.69