Table 2.

The intra- and inter-inter-observer error and the effects caused by pelvic rotation

Pelvic rotation/°	Intra-observer error*	Inter-observer error*	Left AI variance*	Right AI variance*	Total measurement error#	Left AI variance#	Effect	Right AI variance#	Effect
− 12	− 0.1 ± 1.7	− 0.0 ± 2.4	0.5 ± 4.0	0.4 ± 4.0	7.8, − 8.0	8.4, − 7.4	Yes	8.2, − 7.6	Yes
− 9	− 0.0 ± 1.6	0.1 ± 1.6	0.1 ± 3.9	0.1 ± 3.5	6.4, − 6.2	7.6, − 7.6	Yes	6.9, − 6.7	Yes
− 6	− 0.1 ± 1.4	0.2 ± 1.7	− 0.1 ± 1.9	− 0.1 ± 1.3	6.1, − 6.0	3.7, − 3.8	No	2.4, − 2.5	No
− 3	0.0 ± 1.3	0.1 ± 2.1	0.1 ± 1.9	0.0 ± 1.1	6.9, − 6.7	3.7, − 3.6	No	2.1, − 2.1	No
0	− 0.1 ± 1.2	− 0.1 ± 2.4	0.00	0.00	6.8, − 7.2	0	–	0	–
3	0.1 ± 1.1	0.3 ± 2.0	0.1 ± 1.4	− 0.4 ± 1.8	6.4, − 5.5	3.0, − 2.7	No	3.0, − 3.9	No
6	− 0.1 ± 1.1	0.2 ± 1.7	0.4 ± 1.8	− 0.1 ± 1.7	5.6, − 5.3	3.9, − 3.0	No	3.3, − 3.5	No
9	0.3 ± 1.2	0.1 ± 2.3	0.9 ± 3.7	− 0.3 ± 3.9	7.2, − 6.4	8.1, − 6.2	Yes	7.4, − 8.0	Yes
12	0.2 ± 1.5	− 0.1 ± 2.0	1.2 ± 3.6	− 0.4 ± 4.0	7.1, − 6.7	8.2, − 5.9	Yes	7.5, − 8.3	Yes

^✻Expressed as Mean ± SD

^#Expressed as 95% confidence interval