condition mean min max ZT0-3 41.642700000000005 18.99435 52.9782 ZT4-7 16.0066 16.0066 16.0066 ZT8-11 16.915599999999998 16.915599999999998 16.915599999999998 ZT12-15 23.868225000000002 19.787100000000002 27.949350000000003 ZT16-19 31.6484 31.6484 31.6484 ZT20-23 54.90285 54.90285 54.90285