Table 4.

Outputs of different linear mixed model testing the effects of time and zone (touristic or control) on freezing intensity for both trial [model (i)] and at each trial [model (ii), model (iii)].

Model	Freezing Intensity ~ Zone + Time + (1|Trial/Aquarium)
(i) June + August	Random effects
		Groups	Name	Variance	Std. Dev.	n
		Aquarium:Trial	(lntercept)	249.8	15.8	20
		SES	(lntercept)	537.7	23.2	2
		Residual		241.4	15.5
		Number of observations: 100
	Fixed effects
		Estimate	Std error	t-value	p-value
	(Intercept)	107.2	17.61	6.1	0.077	.
	Zone:Touristic	−19.4	7.7	−2.5	0.02	*
	Time	−0.9	1.1	−0.8	0.4
	Freezing Intensity ~ Zone + Time + (1|Aquarium)
(ii) June	Random effects
		Groups	Name	Variance	Std. Dev.	n
		Aquarium	(Intercept)	78.24	8.845	8
		Residual		129.83	11.394
		Number of observations: 40
	Fixed effects
		Estimate	Std error	t-value	p-value
	(Intercept)	94.18	6.4	14.8	<0.0001	***
	Zone:Touristic	−22.3	7.2	−3.1	0.02	*
	Time	−1.75	1.3	−1.38	0.18
	Freezing Intensity ~ Zone + Time + (1|Aquarium)
(iii) August	Random effects
		Groups	Name	Variance	Std. Dev.	n
		Aquarium	(Intercept)	377.8	19.4	12
		Residual		318.2	17.8
		Number of observation: 60
	Fixed effects
		Estimate	Std error	t-value	p-value
	(Intercept)	121.2	9.87	12.28	<0.0001	***
	Zone:Touristic	−17.43	12.13	−1.44	0.18
	Time	−0.34	1.63	−0.21	0.84

Models with additive terms (zone + time) and interaction between terms (zone x time) were first compared using the Akaike's Information Criterion (AIC) so that the most parsimonious model was conserved.

^***< 0.001,

^*< 0.05.