condition mean min max ZT0-3 19.466974999999998 18.7582 20.17575 ZT4-7 23.05125 23.05125 23.05125 ZT8-11 21.401049999999998 21.401049999999998 21.401049999999998 ZT12-15 0 0 0 ZT16-19 26.07995 26.07995 26.07995 ZT20-23 20.490099999999998 20.490099999999998 20.490099999999998