. 2023 Jan 10;13(2):251. doi: 10.3390/ani13020251

Table 2.

Chi-square statistics for copulation.

Independent Variable	Categories Tested	Dependent Variable and Statistics
		Copulation
		# Y	n	% Y	Χ²	df	p	CV
Age	Immature	35	61	57.4	4.81	2	0.090	0.075
	Adult	477	683	69.8
	Elderly	77	119	64.7
Sex	Female	369	504	73.2 ^a	13.78	1	0.000	0.126
Sex	Male	220	359	61.3 ^b	13.78	1	0.000	0.126
Rearing	MR	355	434	81.8 ^a	79.86	2	0.000	0.304
	NOTMR	202	354	57.1 ^b
	UNK	32	75	42.7 ^b
Within MR	Female	213	258	82.6	0.25	1	0.704	0.024
Within MR	Male	142	176	80.7	0.25	1	0.704	0.024
Within NOTMR	Female	133	200	66.5 ^a	16.71	1	0.000	0.217
Within NOTMR	Male	69	154	44.8 ^b	16.71	1	0.000	0.217
Within UNK	Female	23	46	50.0	2.62	1	0.151	0.187
Within UNK	Male	9	29	31.0	2.62	1	0.151	0.187
WB vs. CB	MR/CB	266	304	87.5 ^a	11.00	1	0.001	0.168
WB vs. CB	MR/WB	61	84	72.6 ^b	11.00	1	0.001	0.168
Group-size	Pair	37	62	59.7	6.30	2	0.042	0.085
	Smaller	306	463	66.1
	Bigger	92	246	72.8
Facility-type	Zoo	123	195	63.1 ^a	42.95	2	0.000	0.223
	Research	369	480	76.9 ^b
	Sanctuary	97	188	51.6 ^a

# Y = # subjects reported to engage in the behavior; n = total subjects for which data existed; % Y = % of n (total) subjects reported to engage in behavior; X² = chi-square value; df = degrees freedom; p = probability/chi-square; CV = Cramer’s V measure of association between independent and dependent variable. Bolded text indicates significant differences between categories based on a chi-square test. Superscripts indicate column proportions significantly different pairwise after Bonferroni correction at alpha = 0.05.