Table 1.

Difference test for gender, age, grade, and duration of closure (M ±SD).

Variable	Group	Problematic smartphone use	Mental health problem
Gender	Male	3.63 ± 0.80	2.70 ± 0.81
	Female	3.30 ± 0.92	2.21 ± 0.86
	t	5.80***	9.14***
Age	18–20	3.42 ± 0.80	2.40 ± 0.81
	21–22	3.51 ± 0.90	2.49 ± 0.87
	23–24	3.45 ± 0.83	2.47 ± 0.87
	25 and over	3.32 ± 1.03	2.36 ± 0.98
	F	1.10	0.80
Grade	①Freshmen	3.54 ± 0.90	2.50 ± 0.91
	②Sophomores	3.49 ± 0.89	2.53 ± 0.85
	③Juniors	3.59 ± 0.79	2.57 ± 0.83
	④Seniors	3.41 ± 0.93	2.47 ± 0.89
	⑤Postgraduates	3.15 ± 0.89	2.00 ± 0.80
	F	6.69***	12.09***
	LSD	⑤<①②③④	⑤<①②③④
Duration of closure	①Less than two weeks	3.52 ± 0.98	2.56 ± 0.93
	②Half to one month	3.63 ± 0.78	2.70 ± 0.78
	④One to one and a half months	3.57 ± 0.79	2.61 ± 0.82
	⑤One and half to two months	3.38 ± 0.99	2.28 ± 0.91
	⑥Two months and over	3.18 ± 0.88	2.04 ± 0.79
	W	6.84***	25.85***
	Tamhane	⑤<①②③	⑤④<①②③

*p <0.05, **p <0.01,

^***p <0.001.

Due to heterogeneity of variance, it was reported as Welch values in duration of closure difference tests and as F values for the others.