condition mean min max ZT0-3 10.1974275 8.441205 11.95365 ZT4-7 2.537785 2.537785 2.537785 ZT8-11 3.2034849999999997 3.2034849999999997 3.2034849999999997 ZT12-15 0 0 0 ZT16-19 5.290185 5.290185 5.290185 ZT20-23 7.244574999999999 7.244574999999999 7.244574999999999