Table 4.

Results of main intervention effects analysis using linear mixed models

Outcome Variable	Multilevel Linear Model	T1-T2					T2-T3					T1-T3
	Predictor Variable	df num	def denom	F	p	η²p	df num	def denom	F	p	η²p	df num	def denom	F	p	η²p
Social Skills	main effect time	1	405.83	0.024	0.877		1	365.58	0.084	0.772		1	393.364	0.553	0.458
	main effect group	1	22.14	0.251	0.621		1	21.13	1.514	0.232		1	23.267	1.697	0.205
	interaction time x group	1	405.83	0.429	0.512		1	365.58	6.829	0.009*	0.018	1	393.364	6.390	0.012*	0.015
Classroom Climate Student	main effect time	1	409.22	20.982	<0.001**	0.051	1	374.56	0.670	0.413		1	412.232	20.296	<0.001**	0.046
	main effect group	1	21.40	0.838	0.370		1	20.09	0.506	0.485		1	21.470	1.260	0.274
	interaction time x group	1	409.22	2.132	0.145		1	374.56	0.483	0.487		1	412.232	0.309	0.579
Classroom Climate Teacher	main effect time	1	418.51	0.051	0.822		1	380.90	0.005	0.945		1	398.859	0.038	0.845
	main effect group	1	19.59	0.338	0.567		1	18.78	1.109	0.305		1	18.831	2.118	0.162
	interaction time x group	1	418.51	0.008	0.928		1	380.90	3.392	0.066		1	398.859	3.158	0.076
Peer Connectedness	main effect time	1	405.48	0.181	0.670		1	367.57	0.004	0.948		1	406.941	0.889	0.346
	main effect group	1	21.19	0.612	0.442		1	21.07	0.000	0.984		1	22.278	0.000	0.985
	interaction time x group	1	405.48	0.122	0.726		1	367.57	3.573	0.059		1	406.941	4.576	0.033*	0.011
Happiness	main effect time	1	400.23	2.569	0.109		1	371.38	0.165	0.684		1	393.365	6.242	0.013*	0.016
	main effect group	1	20.14	0.892	0.356		1	20.13	1.174	0.291		1	20.412	3.109	0.093
	interaction time x group	1	400.23	0.740	0.390		1	371.38	7.400	0.007*	0.019	1	393.365	3.124	0.078

p values in bold indicate statistical significance

*Indicates statistical significance at <0.05

**Indicates statistical significance at <0.001