Table 2. The mixed-effect results of NASA-TLX from the best fitted model.

					95% Confidence interval
Scale	Variable	Mean	Standard error	p Value	Lower limit	Upper limit
Mental Demand	Intercept	46.59	3.53
	Time	0.65	0.13	<0.001**	-5.41	-1.23
	Condition	-3.32	1.06	0.001*	0.36	0.88
Physical Demand	Intercept	31.53	4.15
	Time	1.74	0.14	<0.001**	1.45	2.02
Temporal Demand	Intercept	41.55	3.15
	Condition	-8.12	1.28	<0.001**	-10.64	-5.59
Performance	Intercept	49.65	3.01
	Time	0.63	0.21	0.002*	0.22	1.04
	Condition	-14.09	1.67	< .001**	-17.38	-10.81
Frustration Level	Intercept	40.78	3.95
	Time	1.37	0.18	<0.001**	1.01	1.73
	Condition	-9.41	1.48	<0.001**	-12.33	-6.48

* p<0.05

**p<0.001.