Table 3.

Correlation matrix for subjective measures of sleep quality, daytime sleepiness, level of arousal and actigraphic measures of sleep

		PSQI	ESS	SSS	Sleep efficiency	Time asleep	Awakenings	Time awake	Avg. time awake	Sleep latency
PSQI	Pearson r	1	0.250*	0.293**	−0.305**	−0.198	−0.233*	0.211	0.462**	−0.003
	Sig. (2-tailed)		0.025	0.009	0.007	0.078	0.041	0.066	<0.005	0.978
	N	80	80	78	77	80	77	77	77	76
ESS	Pearson r	0.250*	1	0.273*	0.108	−0.287**	−0.369**	−0.228*	0.156	0.004
	Sig. (2-tailed)	0.025		0.015	0.35	0.01	0.001	0.046	0.176	0.973
	N	80	80	78	77	80	77	77	77	76
SSS	Pearson r	0.293**	0.273*	1	0	−0.098	−0.201	−0.131	0.072	0.249*
	Sig. (2-tailed)	0.009	0.015		0.998	0.391	0.084	0.263	0.54	0.032
	N	78	78	78	75	78	75	75	75	74

PSQI: Pittsburgh Sleep Quality Index, ESS: Epworth Sleepiness Scale, SSS: Stanford Sleepiness Scale.

^**p<0.01,

^*p<0.05.