Table 2.

Comparisons of diary- and actigraphy-derived sleep variables (subsample n = 18)

Sleep variable, hh : mm	Method (mean ± SD)		Paired samples t-test, t	Pearson's correlation, r
	Diary	Actigraphy
Sleep onset timea	20:15 ± 1:00	20:23 ± 1:03	−1.52	.98***
Wake timea	07:31 ± 0:37	07:33 ± 0:38	−1.36	.99***
Nap durationb	0:12 ± 0:25	0:17 ± 0:14	−1.1	.81***

^aMean of 5 nights.

^bMean of 4 days.

^***p ≤ .001.