condition mean min max ZT0-3 4.2 4.2 4.2 ZT4-7 2.4 2.4 2.4 ZT8-11 4.4 4.4 4.4 ZT12-15 2.1500000000000004 2.1500000000000004 2.1500000000000004 ZT16-19 4.1 4.1 4.1 ZT20-23 3.15 3.15 3.15