condition mean min max ZT0-3 7.830801666666666 6.418555 8.97725 ZT4-7 4.621535 4.621535 4.621535 ZT8-11 3.600225 3.600225 3.600225 ZT12-15 2.0835074999999996 1.668205 2.4988099999999998 ZT16-19 4.57569 4.57569 4.57569 ZT20-23 9.465055 9.465055 9.465055