Table 7.

Tests for demographic differences between samples

	Consent versus RCT sample			Consent versus epidemiology sample			RCT versus actigraphy sample		RCT versus epidemiology sample			RCT versus caseness RCT (CSHQ > 41)
Direction	χ2†	P-value	Direction	χ 2	P-value	χ 2	P-value	Direction	χ 2	P-value	Direction	χ 2	P-value
Sex, n (%)		2.25	0.134		0.1	0.75	0.07	0.793		2.62	0.455	RCT < caseness	5.1	0.023*
Age in years, n (%)	Consent < RCT	10.79	0.005**		0.47	0.789	0.34	0.845		11.9	0.064		1.07	0.059
Free school meals, n (%)	Consent < RCT	4.37	0.037*	Consent > epid	17.84	0.000***	0.89	0.346	RCT > Epid	22.33	0.000***	RCT < caseness	11.42	0.002**
Ethnicity, n (%)	Consent < RCT	10.32	0.035*		2.3	0.681	0.99	0.911		12.92	0.375		3.02	0.552

	t-value	P-value	t-value	P-value	t-value	P-value	t-value	P-value	t-value	P-value
Weight (kg)	−1.59	0.111	−1.696	0.242	RCT < acti −2.08	0.038*	−0.285	0.77	0.77	0.442

RCT, randomized controlled trial.

^***P < 0.001;

^**P < 0.01;

^*P < 0.05.

^†χ² tests.