Table 4 Results of water sampling and lead analysis from 100,000 homes, and sensitivity to detecting water lead spikes.
Round | Number (%) of homes with first spike occurrence | Cumulative Frequency (%) of homes with at least 1 spike | Homes with undetected spikes | Cumulative sensitivity |
|---|---|---|---|---|
1 | 2021 (2.02) | 2021 (2.02) | 29,699 | 6.37% |
2 | 2949 (2.95) | 4970 (4.97) | 26,750 | 15.67% |
3 | 2589 (2.59) | 7559 (7.56) | 24,161 | 23.83% |
4 | 2353 (2.35) | 9912 (9.91) | 21,808 | 31.25% |
5 | 2299 (2.3) | 12,211 (12.21) | 19,509 | 38.50% |
6 | 2183 (2.18) | 14,394 (14.39) | 17,326 | 45.38% |
7 | 2147 (2.15) | 16,541 (16.54) | 15,178 | 52.15% |
8 | 2075 (2.08) | 18,616 (18.62) | 13,104 | 58.69% |
9 | 1959 (1.96) | 20,575 (20.57) | 11,145 | 64.86% |
10 | 2049 (2.05) | 22,624 (22.62) | 9096 | 71.32% |
11 | 1912 (1.91) | 24,536 (24.54) | 7184 | 77.35% |
12 | 1844 (1.84) | 26,380 (26.38) | 5340 | 83.17% |
13 | 1857 (1.86) | 28,237 (28.24) | 3483 | 89.02% |
14 | 1762 (1.76) | 29,999 (30.00) | 1721 | 94.57% |
15 | 1721 (1.72) | 31,720 (31.72) | 0 | 100.00% |
