. 2016 Sep 29;15:160. doi: 10.1186/s12939-016-0438-1

Table 7.

Within-group comparison of median values and quartiles (q₁-q₃) T₀-T₁ for sleep hours per educational group

	T₀		T₁
Education level	High	Low	High	Low
Country
Sleep duration weekdays (h/day) ^a
Portugal	3 (2–3)	2 (2–3)	3 (2–3)	2 (2–3)
The Netherlands	3 (3–3)	3 (2–3)	3 (3–3)	3 (3–3)
Sleep duration weekend days (h/day) ^a
The Netherlands	3 (3–3)	3 (2–3)	3 (3–3)	3 (3–3)

^a Response categories: 1. 6 h or less/per night 2.7 h/per night 3.8 h/per night 4.9 h/ per night 5.10 h/per night 6.More than 10 h per night