Table 2. Fixed and random effects for the linear mixed model that measures the effect of the parameterization used on the accuracy.

The front-ends under consideration are MFCC (intercept), LDA1, LDA2, NMF_CC, H_CC + G_NMF and the combinations MFCC + H_CC + G_NMF and NMF_CC + H_CC + G_NMF. The inclusion of the first derivatives is indicated with the suffix “+ Δ‘”. For the fixed effect (parameterization), the classification rate ([%]) estimates, standard errors and t-values are shown. The statistical significance at p < 10⁻⁴ is marked with ***, p < 10⁻³ is marked with ** and p < 0.05 is marked with *. For the random effects (bird species and fold), variances and standard deviations are reported.

Fixed effects:
	Estimate	Std. Error	t value
Intercept	69.623	4.633	12.800 ***
LDA1	−12.636	1.681	−7.519 ***
LDA2	−3.433	1.681	−2.043 *
NMF_CC	1.897	1.681	1.129
H_CC + G_NMF	−3.141	1.681	−1.869
MFCC + Δ	3.070	1.681	1.827
NMF_CC + Δ	5.963	1.681	3.549 ***
MFCC + H_CC + G_NMF	4.070	1.681	2.422 *
NMF_CC + H_CC + G_NMF	4.280	1.681	2.547 *
MFCC + H_CC + G_NMF + Δ	4.393	1.681	2.614 **
NMF_CC + H_CC + G_NMF + Δ	6.119	1.681	3.641 ***
Random effects:
Groups		Variance	Std. Dev.
Species		236.884	15.391
Fold		1.871	1.368
Residual		101.668	10.083
Number of obs: 792, groups: Species, 12; Fold, 6