Table 1.

ANOVA results for simulation factors impacting power for the slopes difference test.

Type of effect	Factor	F	df	p	${\eta }^2$
Main	Number of waves	803.913*	2	<0.001	0.048
	Size of class	809.524*	2	<0.001	0.048
	Number of classrooms	343.182*	3	<0.001	0.031
	Proportion in treatment	74.721*	1	<0.001	0.002
	Effect size	11433.155*	2	<0.001	0.684
	ICC	0.018	2	0.982	<0.001
Interaction	Waves: class	0.569	4	0.685
	Waves: classrooms	0.394	6	0.883
	Waves: treatment	0.360	2	0.698
	Waves: effect	531.712*	4	<0.001	0.064
	Waves: ICC	0.048	4	0.996
	Class: classrooms	0.366	6	0.900
	Class: treatment	0.102	2	0.903
	Class: effect	535.990*	4	<0.001	0.064
	Class: ICC	0.013	4	1.000
	Classrooms: treatment	0.392	3	0.759
	Classrooms: effect	212.300*	6	<0.001	0.038
	Classrooms: ICC	0.082	6	0.998
	Treatment: effect	41.238*	2	<0.001	0.002
	Treatment: ICC	0.135	2	0.135
	Effect: ICC	0.022	4	0.999

*Indicates statistically significant at the 0.05 level; ${\eta }^2$ represents the proportion of the total variance in the DV that can be explained by the factor; only ${\eta }^2$ for statistically significant interaction effects shown; residual df = 576; a bold ${\eta }^2$ represents an effect size above the cutoff of 0.03.