condition mean min max ZT0-3 6.03399 5.880635 6.1873450000000005 ZT4-7 6.17035 6.17035 6.17035 ZT8-11 6.87482 6.87482 6.87482 ZT12-15 0 0 0 ZT16-19 6.478165000000001 6.478165000000001 6.478165000000001 ZT20-23 6.74302 6.74302 6.74302