condition mean min max ZT0-3 28.353069 28.353069 28.353069 ZT4-7 20.125283500000002 20.125283500000002 20.125283500000002 ZT8-11 21.3581595 21.3581595 21.3581595 ZT12-15 18.8888685 18.8888685 18.8888685 ZT16-19 19.649994 19.649994 19.649994 ZT20-23 20.6018275 20.6018275 20.6018275