TABLE 3.

Regression analysis (Playing hours).

	A. Prevalence - Polynomial Coding
Contrast	Beta	Std. Error	z	p
Linear	0.67	0.54	1.24	0.21
Quadratic	–1.78	0.48	–3.68	0.00*
Cubic	0.41	0.68	0.61	0.54
4th degree	–0.83	0.67	–1.24	0.21
5th degree	–1.99	0.79	–2.53	0.01*
6th degree	0.96	0.66	1.46	0.15
	B. Prevalence - Treatment Coding (vs. 1 - 3 h)
Contrast	Beta	Std. Error	z	p
4 - 6 h	0.80	0.54	1.47	0.14
7 - 9 h	3.58	1.08	3.33	0.00*
10 - 12 h	1.22	0.54	2.24	0.03
13 - 15 h	1.34	0.62	2.15	0.03
16 - 18 h	2.71	1.10	2.47	0.01*
19+ h	0.66	0.47	1.41	0.16
	C. Severity - Polynomial Coding
Contrast	Beta	Std. Error	t	p
Linear	1.96	0.66	2.96	0.00*
Quadratic	–1.65	0.61	–2.69	0.01*
Cubic	–0.08	0.69	–0.12	0.91
4th degree	–0.73	0.73	–1.00	0.32
5th degree	–1.76	0.72	–2.45	0.02*
6th degree	0.86	0.66	1.31	0.19
	D. Severity - Treatment Coding (vs. 1 - 3)
Contrast	Beta	Std. Error	t	p
4 - 6 h	0.64	0.94	0.68	0.50
7 - 9 h	3.40	0.89	3.82	0.00*
10 - 12 h	1.73	0.90	1.93	0.06
13 - 15 h	2.28	0.99	2.30	0.02*
16 - 18 h	3.72	1.12	3.32	0.00*
19+ h	1.77	0.84	2.12	0.04

bold face: p < 0.05; *p < 0.025.