TABLE 4.

Correlation Coefficients^a for Exposure Variables (log-transformed) and Study Variables, NCCLS Contact Current Study

	Log(Bavg)b	Log(Vbath)c	Log(VW-E)d
Log(Bavg)b		0.10	0.15
Log(Vbath)c			0.08
Log(VW-E)d
Hispanic ethnicity	<0.01	0.03	<0.01
Race (White vs. non-White)	0.01	0.02	0.03
Household incomee	0.02	0.03	0.01
Year when house was builte	0.25	0.38	0.06
Residence type (Single-family vs. other)	0.13	0.12	0.01
Location (urban/non-urban)	0.18	0.08	0.15
Time between diagnosis/reference date and measurement	0.03	<0.01	0.03
Season of measurement (Summer vs. Fall or Spring)	0.03	0.12	0.06
Ambient temperature at measurement	<0.01	0.12	0.06
Time at measurement	0.07	0.02	<0.01

^aSpearman coefficients unless indicated otherwise.

^bB_avg is the indoor magnetic-field measurement.

^cV_bth is the indoor contact voltage measurement (voltage measured between the faucet and the drain in the bathtub).

^dV_W-E is the outdoor contact voltage measurement (voltage measured between the water main and pole in the ground).

^ePearson coefficients.