Table 8.

Ridge regression results on PA.

K = 0.155	Nonnormalized coefficient		Normalized coefficient	t	P	R2	Adjusted R2	F
	B	Standard error	Beta
Constant	− 2.981	1.654	–	− 1.803	0.078*	0.971	0.968	310.949(0.000***)
Windy Sound	0.272	0.013	0.287	20.214	0.000***
Birdsong	0.226	0.021	0.225	10.65	0.000***
Hydroacoustics	0.123	0.025	0.119	5.002	0.000***
Insect Chirping	0.048	0.026	0.045	1.809	0.077*
Combined Sound	0.306	0.019	0.288	16.241	0.000***

1. Dependent variable: PA 2. ***, ** and * represent significance levels of 1, 5 and 10% respectively.