. 2021 Mar 3;8(3):188. doi: 10.3390/children8030188

Table 2.

Sleep duration and sleep quality in boys and girls in the three cities.

Variable	Sex	Seville	Reykjavik	Tartu
Sleep duration (min.)	Boys	439 ± 63 *	451 ± 66	452 ± 52 *
Sleep duration (min.)	Girls	450 ± 62 ^A	442 ± 56	429 ± 53
Sleep quality (index)	Boys	4.79 ± 2.78 *^{, B}	4.02 ± 2.10 *^{, C}	4.54 ± 2.26
Sleep quality (index)	Girls	5.41 ± 2.96 ^B	4.78 ± 2.34 *	5.13 ± 2.35

* Statistical difference between boys and girls in the same city; ^A Significance of the difference between Sevilla and Tartu; ^B Significance of the difference between Sevilla and Reykjavik; ^C Significance of the difference between Reykjavik and Tartu.