condition mean min max ZT0-3 2.1 2.1 2.1 ZT4-7 2.3 2.3 2.3 ZT8-11 1.7999999999999998 1.7999999999999998 1.7999999999999998 ZT12-15 2.65 2.65 2.65 ZT16-19 4.55 4.55 4.55 ZT20-23 15.95 15.95 15.95