condition mean min max ZT0-3 3.4000000000000004 3.4000000000000004 3.4000000000000004 ZT4-7 2.4 2.4 2.4 ZT8-11 4.1 4.1 4.1 ZT12-15 2.4 2.4 2.4 ZT16-19 2.7 2.7 2.7 ZT20-23 3.8 3.8 3.8