Table 2. Average cooperation, null-hypothesis, and p-values.

Sample	Full sample	Boys sample	Girls sample	Null	p-value (MW)
Full sample	4.11	4.24	3.99	H0: B = G**	0.5911
Colombian sample	4.00	4.46	3.54	H0: B = G	0.0291
Swedish sample	4.25	3.98	4.55	H0: B = G	0.0664
Null	H0: C = S*	H0: C = S	H0: C = S
p-value (MW)	0.0825	0.4426	0.0006

* H₀: C = S refers to the null-hypothesis of no differences in cooperation between Colombia (C) and Sweden (S) with the respective samples.

** H₀: B = G refers to the null-hypothesis of no differences in cooperation between Boys (B) and Girls (G) with the respective samples.