Table 2.

Summary statistics (Spearman's correlations)

Variables compared and genotype	In vivo			In vitro
	n	rs	P	n	rs	P
Circadian period vs. morningness-eveningness score
All	31	−0.369	0.041	32	−0.223	0.220
PER34/4	13	−0.500	0.082	13	−0.176	0.565
PER34/5	6	−0.029	0.957	8	−0.491	0.217
PER35/5	12	−0.497	0.100	11	−0.119	0.727
Circadian period vs. timing of melatonin onset relative to habitual bed time
All	31	0.420	0.019	30	−0.203	0.281
PER34/4	13	0.367	0.218	12	−0.102	0.752
PER34/5	6	0.371	0.469	7	−0.433	0.333
PER35/5	12	0.509	0.091	11	−0.124	0.717
In vivo period vs. in vitro period
All	28	0.024	0.903
PER34/4	12	−0.282	0.375
PER34/5	6	0.160	0.827
PER35/5	10	0.404	0.247

Nonparametric correlations between in vivo and in vitro period and morningness-eveningness score, as well as timing of melatonin onset relative to habitual bedtime.