Table 1.
Paired comparisons (Wilcoxon tests) of behavioural and acoustical variables in playback experiments of medium adult versus medium subadult. (NLP, nonlinear phenomena. Formant spacing, from which apparent Vocal tract length (VTL) is directly calculated, is presented in square brackets.)
| variable | medium adult (means±s.e.) | medium subadult (means±s.e.) | Z | n | significance | ||
|---|---|---|---|---|---|---|---|
| behavioural variables | |||||||
| duration of attention (s) | 70.1 | 5.8 | 48.8 | 8.6 | −2.272 | 13 | p=0.0139 |
| number of common roars | 6.31 | 1.58 | 3.10 | 0.72 | −2.476 | 13 | p=0.0133 |
| number of harsh roars | 0.69 | 0.17 | 0.23 | 0.12 | −2.460 | 13 | p=0.0231 |
| acoustic variables in first response roar | |||||||
| average apparent VTL (cm) | 70.1 | 0.8 | 65.8 | 2.0 | −2.668 | 9 | p=0.0076 |
| [average formant spacing (Hz)] | 250 | 3 | 269 | 11 | −2.668 | 9 | p=0.0076 |
| maximum apparent VTL (cm) | 74.5 | 0.8 | 70.2 | 1.6 | −2.668 | 9 | p=0.0077 |
| [minimum formant spacing (Hz)] | 235 | 3 | 251 | 7 | −2.668 | 9 | p=0.0077 |
| proportion of responses with NLP | 0.89 | 0.11 | 0.39 | 0.16 | −2.121 | 9 | p=0.0339 |