Table 2.
Multiple regression analysis of variables predicting the direction and degree of response to high- versus control-performance stimuli. Results determined by model selection (AIC) indicate the full model as best-fit, which includes the vocal performance of both playback stimuli and subject males as predictor variables for PC3 approach/duration (r2 = 0.725, n = 19, d.f. = 18, F = 4.15, p = 0.018). Asterisk (*) denotes individual variables that achieved significance within the model. See text and figure 2c,d for further explanation.
| predictor variables | β | F | p < |
|---|---|---|---|
| playback variables | |||
| % trill increased | –0.07 | 9.7 | 0.01* |
| trill rate (Hz) | 0.39 | 5.8 | 0.04* |
| notes per syllable | 0.81 | 3.9 | 0.08 |
| trill rate (Hz) × notes/syllable | –0.28 | 1.9 | 0.20 |
| subject male variables | |||
| vocal deviation | 274.3 | 8.1 | 0.02* |
| trill rate | 31.0 | 8.0 | 0.02* |
| frequency bandwidth | 0.27 | 8.0 | 0.02* |