condition mean min max ZT0-3 3.6999999999999997 3.6999999999999997 3.6999999999999997 ZT4-7 9.3 9.3 9.3 ZT8-11 12.4 12.4 12.4 ZT12-15 6.65 6.65 6.65 ZT16-19 3.2 3.2 3.2 ZT20-23 7.15 7.15 7.15