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Table 1 Sample characteristics

From: A cross-sectional study of well water arsenic and child IQ in Maine schoolchildren

Measures Mean ± SD or %(n)
Child characteristics  
Male % 53.31 (145)
Child age 9.67 ± 1.18
Length of current residence 7.34 ± 2.37
School Grade 3.80 ± 0.81
School District  
RSU-A 28.68% (78)
RSU-B 18.75% (51)
RSU-C 52.57% (143)
Race % White 95.2 (259)
Family characteristics  
Paternal age (N = 267) 43.64 ± 6.66
Paternal education  
≤High school graduate 29.04% (79)
Some college 26.84% (73)
College graduate 22.43% (61)
Graduate 19.85% (54)
Any post-graduate 1.84% (5)
Maternal age 40.72 ± 6.02
Maternal education  
≤High school graduate 13.60% (37)
Some college 34.93% (95)
College graduate 32.35% (88)
Any post-graduate 19.12% (52)
Maternal IQ (WASI) 114.84 ± 11.31
HOME Total (n = 243) 52.57 ± 3.73
HOME category  
Missing 10.66 ± 29
Low scores (<53) 40.81 ± 111
High scores (≥53) 48.53 ± 132
Number of other children in home 1.29 ± 0.91
Exposure characteristics  
Overall well water As (μg/L) 9.88 ± 15.06
Water As < 5 μg/L (n = 141) 1.24 ± 1.37
10 > WAs >5 μg/L (n = 46) 7.37 ± 1.34
20 > WAs > 10 μg/L (n = 52) 14.80 ± 3.06
WAs > 20 μg/L (n = 33) 42.55 ± 20.43
% Well water As ≥ 10 μg/L 31.25 (85)
Nail As (μg/g) 4.65 ± 4.60
Child Intelligence  
Full Scale 110.32 ± 12.60
Verbal Comprehension 114.26 ± 15.78
Perceptual Reasoning 108.57 ± 13.25
Working Memory 102.72 ± 12.20
Processing Speed 103.34 ± 13.44