condition mean min max ZT0-3 4.550000000000001 4.550000000000001 4.550000000000001 ZT4-7 4.5 4.5 4.5 ZT8-11 15.549999999999999 15.549999999999999 15.549999999999999 ZT12-15 2.85 2.85 2.85 ZT16-19 6.5 6.5 6.5 ZT20-23 4.8 4.8 4.8