HARDBACK
\$49.95

• #### Index 269-279

Table F.1

Probability Density Functions Used in the Calculation of Risk of Cancer Posed by Ingestion of Radon Gas in Water (following notation of EPA 1995)

 Variability Uncertainty Parameter Distribution Type Distribution Values Distribution Type Distribution Values C (concentration of radon in water, pCi/L[water]) Lognormal distribution, LN(µ) C = LN(µ,σ) µ = TS(m,s,n) (σ)2=IChi(s,n) Student t, distribution, TS(m,s,n) Inverse chi-squared distribution, IChi(s,n) n= 10 m = ln(200) s = ln(1.85) V (volume of water ingested, L/d) Lognormal distribution, LN(µ,σ) V = LN(µ,σ) µ=TS(m,s,n) (σ)2=IChi(s,n) Student t distribution, TS(m,s,n) Inverse chi-squared distribution, IChi(s,n) n=100 m = ln(0.526) s = ln(1.922) F (fraction remaining) Beta distribution, B(m,md,min,max) F=B(m,md,min,max) min=0.5 max=1 m=U(a,b) md=U(m,max) or U(min,m) Uniform distributions U(a,b) U(m,max) a=0.7 b=0.9 min = 0.5 max=1 RF (risk factor, cancer-death risk per person per pCi ingested) This factor has uncertainty only RF=LN(µ,σ) µ= ln(1.24 × 10-11σ = ln(2.42) Calculated individual risk Uncertainty==> Variability 5th percentile mean 95th percentile 5th percentile 1.7 × 10-8 1.3 × 10-7 4.0 × 10-7 median 8.3 × 10-8 6.2 × 10-7 1.9 × 10-6 95th percentile 3.4 × 10-7 2.6 × 10-6 7.9 × 10-6 m=mean value derived from a sample s=standard deviation of a sample n=sample size md=mode of a sample µ=mean value of ln(x) in a lognormal distribution µ=standard deviation of ln(x) in a lognormal distribution

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001