Table 2.

Correlation coefficients between measured PCE concentrations in water samples and model-generated estimates

	No. of Samples	Spearman Correlation Coefficient	P-Value
All Samples	88	0.48	< 0.001
According to:
Complexity of pipe configurationa
Simple	31	0.51	0.003
Complex	57	0.38	0.003
Magnitude of flowa
High (> 19 homes)	19	0.37	0.1
Medium (3–19 homes)	33	0.30	0.09
Low (< = 2 homes)	36	0.54	0.0007
Position along pipea
End	44	0.44	0.003
Beginning/Middle	44	0.44	0.003
Overestimated housing densitya
Yes	25	0.52	0.008
No	63	0.47	0.0001
Season sampleda
Spring	74	0.50	< 0.0001
Autumn	14	0.58	0.03
Water fixture sampleda
Tap or spigot	10	0.84	0.002
Hydrant	18	0.34	0.2
Unknown	60	0.38	0.003
Sampling personnela
Sampler 1	69	0.45	0.0001
Sampler 2	18	0.57	0.01
Sampler 3	1	---b	---b
Towna
Barnstable	7	---c	---c
Bourne	16	0.53	0.03
Brewster	7	0.018	1.0
Chatham	6	0.39	0.4
Falmouth	6	0.49	0.3
Provincetown	5	---c	---c
Sandwich	9	0.53	0.1
Plymouth	25	0.56	0.003
Wareham	7	0.48	0.3
Pipe installation yeara
1968–1972	23	0.42	0.05
1973–1976	32	0.56	0.0008
1977–1980	33	0.37	0.03

^a See text for definitions and further description.

^b Analyses were not conducted because of the small sample size.

^c Analyses were not conducted because all water samples had undetectable PCE levels.