condition mean min max ZT0-3 4.4 4.4 4.4 ZT4-7 3.0 3.0 3.0 ZT8-11 2.0 2.0 2.0 ZT12-15 1.9000000000000001 1.9000000000000001 1.9000000000000001 ZT16-19 1.7 1.7 1.7 ZT20-23 8.6 8.6 8.6