. 2021 Apr-Jun;14(2):169–174. doi: 10.5935/1984-0063.20200048

Table 2.

Reliability analysis of the 4-item questionnaire.

Items and variables in children	rho (N=55)	alpha (N=237)
Wake up time on weekdays	0.34^**	0.68
Bedtime on weekdays	0.35^**	0.60
Time spent in bed^a on weekdays	0.09	0.49
All items		0.63
Wake up time on weekend days	0.30^**	0.98
Bedtime on weekend days	0.18	0.38
Time spent in bed^a on weekend days	0.08	0.21
All items		0.79
Wake up time on total days	0.37^**
Bedtime on total days	0.33^**
Time spent in bed^a on total days	0.35^*
Items and variables in adolescents	rho (N=106)	alpha (N=258)
Wake up time on weekdays	0.56^**	0.96
Bedtime on week days	0.54^**	0.59
Time spent in bed^a on weekdays	0.19	0.08
All items		0.72
Wake up time on weekend days	0.92^**	0.99
Bedtime on weekend days	0.38^**	0.25
Time spent in bed^a on weekend days	0.24	0.18
All items		0.79
Wake up time on total days	0.87^**
Bedtime on total days	0.41^**
Time spent in bed^a on total days	0.74^**

Moderate (or above) value of spearman correlation was set in rho≥0.30; alpha: Cronbach-alpha coefficient; rho: Spearman correlation coefficient; ^a: Based on the equation: (bedtime in clock time) - (wake up in clock time);

p<0.05;

^**

p<0.001.