condition mean min max ZT0-3 3.35 3.35 3.35 ZT4-7 27.6 27.6 27.6 ZT8-11 9.15 9.15 9.15 ZT12-15 2.1500000000000004 2.1500000000000004 2.1500000000000004 ZT16-19 7.6 7.6 7.6 ZT20-23 2.45 2.45 2.45