. Author manuscript; available in PMC: 2010 Apr 15.

Published in final edited form as: Environ Sci Technol. 2009 Apr 15;43(8):2714–2719. doi: 10.1021/es803141m

Table 2.

Summary Statistics of Groundwater As in Four Clusters in greater Augusta area

	clusters	Manchester	Litchfield	Sidney	Chelsea
	sampling area (km²)	20	10	2.6	2.6
*2007*	sample size (n)	113	49	62	107
	sampling density (n/km²)	6	5	24	42
	median As (μg/L)	22.2	14.6	4.1	0.9
	inter-quartile range (μg/L)	31.4	37.5	10.2	4.3
	probability of As >10μg/L	78%	57%	29%	7%
*2006*	sample size (n)	21	12	14	16
	sampling density (n/km²)	1	1	5	6
	median As (μg/L)	31.1	22.7	0.2	ND
	probability of As >10μg/L	48%	75%	14%	6%
	kriged probability of As >10μg/L	53%	70%	17%	13%