Calculation of a Health Index of Oil-Paper Transformers Insulation with Binary Logistic Regression

Table 4

Variables evaluation with six factors.

Variables		SE	Wald	Df	Sig.
Water		0.211	1.358	1	0.244
Acidity		25.470	1.261	1	0.261
BDV		0.111	2.365	1	0.124
DF		0.487	0.053	1	0.818
DCG		0.009	1.514	1	0.219
2-Furfuraldehyde		0.376	0.456	1	0.499
Constant		6.957	0.614	1	0.433

Note: : the estimated coefficient; SE: standard error of the estimate; Wald: Wald value; Df: degree of freedom; Sig.: significance value.
Sig. is also used to assess the significance of each coefficient in logistic regression [13]. The smaller the Sig. value is, the more the variable is significantly related to the logistic regression.