Table 1 Summary of the linear models performed to test whether the dependent variables ‘mean speed’, ‘straightness index’, ‘scaling exponents ζ(q)’ and ‘directional entropy’ of sea urchin trajectories were different for the control (n = 29) and predator (n = 21) experiments. df, degrees of freedom
Response variable | Model type | Effect | df | Statistic | P |
|---|---|---|---|---|---|
Straightness index (Is) | Linear model | Treatment | 1 | F = 4.66 | 0.036 * |
Residuals | 48 | ||||
Mean speed | Linear model | Treatment | 1 | F = 11.35 | 0.001 ** |
Residuals | 48 | ||||
Slope of ζ(q) | General Least Squares | Treatment | 1 | χ2 = 9.48 | 0.002** |
Directional entropy | Linear Model | Treatment | 1 | F = 7.02 | 0.011* |
Slope of ζ(q) | 1 | F = 38.52 | 0.000*** | ||
Treatment*Slope ζ(q) | 1 | F = 2.03 | 0.161 | ||
Residuals | 46 |