Table 1. Errors.

Mean and SD of the absolute value of the difference between the coordinates measurement and the actual coordinates.

	Trial1 error(mm)		Trial2 error(mm)
	Mean	SD	Mean	SD
Coordinates in x-axis
Observer1
45°	6.03	3.22	6.73	3.55
60°	2.67	1.36	3.17	1.55
75°	3.85	1.80	3.73	1.75
90°	2.41	1.34	1.32	1.01
Observer2
45°	5.65	3.02	5.73	3.16
60°	2.28	1.37	2.02	1.19
75°	3.06	1.53	2.98	1.57
90°	1.46	1.04	1.58	1.13
Observer3
45°	7.07	3.71	0.98	1.10
60°	2.41	1.34	2.75	1.21
75°	3.66	1.94	3.26	1.73
90°	0.79	0.92	0.98	1.10
Coordinates in y-axis
Observer1
45°	1.03	0.74	0.95	0.78
60°	1.34	0.91	1.50	0.86
75°	0.58	0.78	0.75	0.67
90°	1.04	0.83	1.02	1.09
Observer2
45°	1.13	0.66	1.01	0.64
60°	1.13	0.63	1.17	0.71
75°	0.51	0.65	0.51	0.67
90°	0.77	0.71	0.55	0.49
Observer3
45°	0.85	0.64	0.82	0.61
60°	1.04	0.83	1.33	0.84
75°	0.63	0.70	0.54	0.53
90°	0.61	0.44	0.82	0.61