Table 3. Descriptive statistics of daytime sleepiness (N=133)

Epworth Sleep Scale, ESS	Mean	SD	Variance	Skewness
1. Sitting and reading	1.03	0.768	0.590	0.661
2. Watching TV	0.89	0.731	0.534	0.639
3. Sitting, inactive in a public place	0.60	0.758	0.575	1.132
4. As a passenger in vehicles for an hour without a break	1.41	0.970	0.940	0.118
5. Lying down to rest in the afternoon when circumstances permit	1.92	0.910	0.828	-0.463
6. Sitting and talking to someone	0.23	0.502	0.252	2.556
7. Sitting quietly after a lunch without alcohol	1.28	0.891	0.793	0.269
8. In a car, while stopped for a few minutes in the traffic	0.56	0.802	0.643	1.426
Total score	7.92	3.979	15.834	0.499
Normal group, n(%)	95 (71.4%)
Excessive daytime sleepiness, n(%)	38 (28.6%)