Table 2. The relation between grunting frequencies and rates of aggression and DSI for (a) mothers and daughters and (b) maternal sisters.
| Estimate (β) | S.E. | z | P | |
|---|---|---|---|---|
| (a) Mothers/daughters | ||||
| Aggression rate | 0.193 | 0.306 | 0.633 | 0.527 |
| DSI | -0.029 | 0.046 | -0.632 | 0.527 |
| Aggr. x DSI interaction | 0.053 | 0.055 | 0.967 | 0.334 |
| (b) Sisters | ||||
| Aggression rate | 0.313 | 0.134 | 2.340 | 0.019 |
| DSI | 0.060 | 0.101 | 0.593 | 0.553 |
| Aggr. x DSI interaction | -0.047 | 0.031 | -1.515 | 0.130 |
Results were obtained from a multi-level mixed effect logistic regression model in which the rate of aggression and DSI served as predictor values and the likelihood of grunting (yes/no) during an approach was the dependent variable.