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. Author manuscript; available in PMC: 2015 Jan 7.
Published in final edited form as: Environ Sci Technol. 2013 Dec 16;48(1):157–164. doi: 10.1021/es403863m

Table 3.

Estimated variance components for major PCBs from the random-effects model (Model 1a) with corresponding variance ratios.

Variance Component Estimate (95% Confidence Interval)
Percent of Total Variance
PCB Between-region,
σ^BR2
Intra-regional
between-home,
σ^BH2
Within-home
over time,
σ^WH2
Within-sample,
σ^WS2
λ b OR Exp c σ^BR2σ^Total2 σ^BH2σ^Total2 σ^WH2σ^Total2 σ^WS2σ^Total2
PCB-28 0.04 (0.01, 0.49) 0.22 (0.16, 0.34) 0.33 (0.26, 0.42) 0.07 (0.05, 0.09) 1.5 1.3 6 34 50 10
PCB-52 0.07 (0.02, 0.77) 0.42 (0.33, 0.56) 0.27 (0.21, 0.36) 0.10 (0.08, 0.13) 0.8 1.5 8 49 32 11
PCB-101 0.16 (0.06, 1.68) 0.81 (0.66, 1.04) 0.31 (0.23, 0.43) 0.16 (0.12, 0.21) 0.5 1.6 11 56 21 11
PCB-105 0.15 (0.05, 1.93) 0.97 (0.78, 1.24) 0.31 (0.21, 0.51) 0.28 (0.22, 0.38) 0.5 1.6 9 56 18 16
PCB-118 0.18 (0.06, 1.96) 0.89 (0.71, 1.14) 0.41 (0.32, 0.55) 0.14 (0.11, 0.19) 0.5 1.6 11 55 25 9
PCB-138 0.08 (0.03, 1.23) 0.32 (0.21, 0.52) 0.60 (0.48, 0.78) 0.16 (0.13, 0.22) 1.9 1.3 7 27 52 14
PCB-153 0.14 (0.05, 1.55) 0.78 (0.62, 1.00) 0.34 (0.26, 0.48) 0.15 (0.12, 0.21) 0.5 1.6 10 55 24 11
PCB-180 0.13 (0.04, 1.94) 0.75 (0.59, 0.99) 0.35 (0.25, 0.52) 0.23 (0.18, 0.32) 0.7 1.5 9 52 24 16
a

In this table, Model 1 was fit for 585 observations including 402 samples collected from 201 homes during repeat sample collections, 88 samples from homes that were sampled once, 55 duplicate samples, and 40 inter-batch quality control replicates.

b

Estimated variance ratio, λ=σ^WH2+σ^WS2σ^BR2+σ^BH2

c

Expected odds ratio, ORExpected=exp[ln(ORTrue)1+λ]