Table 2. Results for the Pittsburgh Sleep Quality Index components as a function of the number (considering each of the three study groups) and proportion (considering the total sample) of students who selected each response option.

Component	Group A n = 125 (33.6)	Group B n = 153 (41.1)	Group C n = 94 (25.3)	Students, n (%)	p*
Subjective sleep quality
Very good	10	15	10	35 (9.4)	< 0.0001
Fairly good	65	68	57	190 (51.1)
Fairly bad	43	67	24	134 (36.0)
Very bad	7	3	3	13 (3.5)
Sleep latency
≤ 15 min	32	52	20	104 (28.0)	0.07
16 to 30 min	63	47	48	158 (42.5)
31 to 60 min	25	40	11	76 (20.4)
> 60 min	5	14	15	34 (9.1)
Sleep duration
> 7 h	24	17	18	59 (15.9)	0.10
6 to 7 h	78	110	65	253 (68.0)
5 to 6 h	19	16	10	45 (12.1)
< 5 h	4	10	1	15 (4.0)
Habitual sleep efficiency
> 85	108	132	87	327 (87.9)	0.58
75 to 84	14	19	7	40 (10.8)
65 to 74	2	2	0	4 (1.1)
< 65	1	0	0	1 (0.3)
Sleep disturbances
0	8	6	4	18 (4.8)	0.29
1 to 9	104	122	71	297 (79.8)
10 to 18	13	25	19	57 (15.3)
19 to 27	0	0	0	0 (0)
Use of sleeping medication
Not during the past month	115	142	83	340 (91.4)	0.72
Less than once a week	5	7	4	16 (4.3)
Once or twice a week	2	1	3	6 (1.6)
Three or more times a week	3	3	4	10 (2.7)
Daytime dysfunction
1 to 2	10	34	3	47 (12.6)	< 0.0001
3 to 4	46	55	30	131 (35.2)
5 to 6	32	53	54	139 (37.4)
Every day	37	11	7	55 (14.8)

A: first- and second-year students; B: third- and fourth-year students; and C: fifth- and sixth-year students. *Chi-square test.