condition mean min max ZT0-3 6.3999999999999995 6.3999999999999995 6.3999999999999995 ZT4-7 2.3 2.3 2.3 ZT8-11 4.75 4.75 4.75 ZT12-15 2.4 2.4 2.4 ZT16-19 7.15 7.15 7.15 ZT20-23 19.2 19.2 19.2