condition mean min max ZT0-3 15.35 15.35 15.35 ZT4-7 4.8 4.8 4.8 ZT8-11 21.650000000000002 21.650000000000002 21.650000000000002 ZT12-15 4.4 4.4 4.4 ZT16-19 7.3 7.3 7.3 ZT20-23 15.55 15.55 15.55