. 2004 Nov 22;113(3):342–349. doi: 10.1289/ehp.7412

Table 2.

Summary of intrachild and interchild variability for blood VOC concentrations (ng/mL).

				Intrachild tolerance interval for
		Interchild tolerance interval for population^b		Individual with mean of L_p^c		Individual with mean of μ^d		Individual with mean of U_p^e
Compound	Overall population geometric mean^a (μ)	L_P	U_P	L_IL	U_IL	L_μ	U_μ	L_IU	U_IU
Benzene	0.063	0.026	0.152	0.007	0.097	0.017	0.233	0.042	0.559
Carbon tetrachloride	0.005	0.002	0.011	0.001	0.006	0.002	0.014	0.004	0.030
1,4-Dichlorobenzene	0.242	0.001	56.436	0.000	0.012	0.021	2.728	5.009	635.803
Ethylbenzene	0.033	0.012	0.087	0.004	0.035	0.012	0.092	0.031	0.244
Styrene	0.110	0.027	0.450	0.005	0.149	0.020	0.608	0.082	2.487
Tetrachloroethylene	0.033	0.006	0.173	0.002	0.024	0.009	0.127	0.045	0.661
Toluene	0.117	0.045	0.306	0.017	0.121	0.043	0.315	0.114	0.824
Trichloroethene	0.007	0.005	0.011	0.003	0.008	0.004	0.012	0.007	0.018
1,1,1-Trichloroethane	0.027	0.018	0.041	0.012	0.029	0.017	0.043	0.026	0.064
m-/p-Xylene	0.172	0.074	0.401	0.024	0.230	0.055	0.536	0.129	1.249
o-Xylene	0.039	0.015	0.100	0.006	0.041	0.014	0.105	0.037	0.271

μ = 10^mean[log(^x^)], the estimated geometric mean, calculated by back-transforming the average of within-child mean log concentrations.

(L_P, U_P) = 95% tolerance interval for the population of individual mean serum levels, calculated using between-child SD, σ_P, for the log-transformed data and back-transforming: log(μ) ± 1.96σ_P.

(L _IL, U _IL) = Tolerance interval for an individual with mean serum level equal to the lower tolerance limit of the population, L_P, and calculated using within-child SD, σ_I, and back-transforming: log(L_P) ± 1.96σ_I.

(L _μ, U _μ) = Tolerance interval for an individual with mean serum level equal to the estimated geometric mean of the population, μ, and calculated using within-child SD, σ_I, and back-transforming: log(μ) ± 1.96σ_I.

(L _IU, U _IU) = Tolerance interval for an individual with mean level equal to the upper tolerance limit of the population, U_P, calculated using within-child SD, σ_I, and back-transforming: log(U_P) ± 1.96σ_I.