Table 7. The association of using natural light on subjective variables (alertness, safety, preference, visual comfort, satisfaction and performance).

	Light condition
Variables	Artificial light	Combinational light (natural and artificial)	p.v
Alertness	3.8(1.5)	3.1(1.0)	0.036
Safety	1.1(1.2)	1.2(0.9)	0.70
Preference	10.37(2.80)	7.60(2.30)	0.001
Visual comfort	7.60(3.4)	10.20(3.3)	0.001
Satisfaction	1.5(1.0)	2.3(0.6)	0.001
Performance	2.8(1.0)	2.6(0.9)	0.2