condition mean min max ZT0-3 1.7999999999999998 1.7999999999999998 1.7999999999999998 ZT4-7 2.5 2.5 2.5 ZT8-11 19.75 19.75 19.75 ZT12-15 3.5999999999999996 3.5999999999999996 3.5999999999999996 ZT16-19 3.55 3.55 3.55 ZT20-23 4.45 4.45 4.45