Table 6.

Spearman’s correlations between smartphone addiction, self-esteem, and sleep quality

	Age of first phone	Age of first smartphone	SAS	RSES	PSQI
Age of first phone
Correlation coefficient	1.000	0.644**	0.098*	−0.084	−0.005
Significant (two tailed)		0.000	0.028	0.059	0.912
Age of first smartphone
Correlation coefficient	0.644**	1.000	0.109*	−0.005	0.048
Significant (two tailed)	0.000		0.015	0.905	0.286
SAS
Correlation coefficient	0.098*	0.109*	1.000	−0.251**	0.388**
Significant (two tailed)	0.028	0.015		0.000	0.000
RSES
Correlation coefficient	−0.084	−0.005	−0.251**	1.000	−0.294**
Significant (two tailed)	0.059	0.905	0.000		0.000
PSQI
Correlation coefficient	−0.005	0.048	0.388**	−0.294**	1.000
Significant (two tailed)	0.912	0.286	0.000	0.000

*Significant, **Highly significant. PSQI – Pittsburgh sleep quality assessment; RSES – Rosenberg self-esteem scale; SAS – Smartphone addiction scale