Table 2.

Chronotype differences on Pittsburgh Sleep Quality Index.

PSQI Component Scale	Morning-types (n = 11)	Evening-types (n = 19)	t	p	d
Subjective sleep quality	0.55 ± 0.52	1.42 ± 0.90	2.94	0.002	1.15
Sleep latency	0.55 ± 0.52	1.47 ± 1.26	2.81	0.009	1.10
Sleep duration	0.27 ± 0.90	0.68 ± 0.95	1.17	ns	0.46
Sleep efficiency	0.27 ± 0.47	0.79 ± 1.13	1.75	0.09	0.69
Sleep disturbance	0.64 ± 0.67	0.95 ± 0.71	1.18	ns	0.46
Medications needed to sleep	0.00 ± 0.00	0.16 ± 0.69	0.76	ns	0.30
Daytime dysfunction	0.27 ± 0.65	0.47 ± 0.77	0.73	ns	0.29
TOTAL SCORE (0–21)	2.55 ± 1.57	5.95 ± 4.80	2.84	0.009	1.11

NOTE: Subscale scores range from 0 (not at all during past month) to 3 (3+ times per week). Total scores greater than 5 are considered clinically significant. d = Cohen’s d effect size. PSQI data from 4 participants (2 from each group) was not included due to missing entries.