. Author manuscript; available in PMC: 2014 Apr 11.

Published in final edited form as: Neurotoxicology. 2006 Aug 22;28(1):126–135. doi: 10.1016/j.neuro.2006.08.005

Table 5B.

Correlations between PI and other parameters by stepwise multiple regression analysis

Models	Variables	Unstandardized coefficients (B)	Standardized coefficients (β)	t	p	Adjusted R²
Model I (n = 27)	MnO₂	9.219	0.536	3.544	0.002^**	0.409
Model I (n = 27)	MnRBC	127.638	0.450	2.976	0.007^**
Model II (n = 27)	SIGP	0.119	0.935	13.140	0.000^**	0.868
Model III (n = 27)	SIFW	0.210	0.718	5.156	0.000^**	0.718

Model I: selected independent variables include age, years in employment, initial working age, air MnO₂, concentrations of Mn, Zn, Cu, Fe, Ca and Mg in whole blood, red blood cell and plasma, and all routine blood parameters. Model II: SIGP was added to Model I with same selected independent variables but without MnO₂ and MnRBC. Model III: SIFW was added to Model 1 with same selected independent variables but without blood Cu. Multiple regression analyses revealed the existence of statistically significant correlation between the PI and MnO₂, MnRBC, SIGP, or SIFW.

^**

Highly significant.