condition mean min max ZT0-3 15.95 15.95 15.95 ZT4-7 22.9 22.9 22.9 ZT8-11 5.5 5.5 5.5 ZT12-15 1.15 1.15 1.15 ZT16-19 1.7000000000000002 1.7000000000000002 1.7000000000000002 ZT20-23 2.1 2.1 2.1