condition mean min max ZT0-3 5.050000000000001 5.050000000000001 5.050000000000001 ZT4-7 2.6 2.6 2.6 ZT8-11 13.95 13.95 13.95 ZT12-15 3.2 3.2 3.2 ZT16-19 21.85 21.85 21.85 ZT20-23 2.4 2.4 2.4