Table 3.

Linear mixed model for females’ friendships and plasma oxytocin concentrations.

Variable	B	Standard error
Birth cohort: 2002	348.37**	78.55
Birth cohort: 2003a	–	–
High Rank	128.81	155.83
Middle Ranka	–	–
Low Rank	−193.62	113.34
Play Friendships	224.76**	41.45
Reciprocal Friendships	−210.08*	80.77
Reciprocal Friendships2	−56.57*	19.97
High Rank × Play Friendships	−157.08*	61.79
Middle Rank × Play Friendshipsa	–	–
Low Rank × Play Friendships	−234.60**	61.95
High Rank × Reciprocal Friendships	314.44**	83.13
Middle Rank × Reciprocal Friendshipsa	–	–
Low Rank × Reciprocal Friendships	259.96**	67.05

^aReference category; *p < 0.05; **p < 0.01.