Table 5.

Optimal scale regression analysis of ipsilateral level-IV lymph node metastasis

Variable	Beta	Standardized coefficient std. error	Df	F	Sig	Tolerance		Importance
						After transformation	Before transformation
Primary tumor size	0.150	0.051	1	8.730	0.003	0.975	0.961	0.164
ETE	-0.127	0.052	1	5.884	0.016	0.962	0.963	0.146
Prelaryngeal LNM	-0.071	0.046	1	2.357	0.126	0.973	0.876	0.003
Pretracheal LNM	0.149	0.055	1	7.415	0.001	0.884	0.849	0.216
Ipsilateral paratracheal LNM	0.251	0.049	1	26.079	0.000	0.889	0.846	0.472

ETE: Extrathyroid extension; LNM: Lymph node metastasis.