condition mean min max ZT0-3 8.710326666666667 5.81579 11.87505 ZT4-7 8.937195 8.937195 8.937195 ZT8-11 3.3400100000000004 3.3400100000000004 3.3400100000000004 ZT12-15 2.5274674999999998 2.1898999999999997 2.8650349999999998 ZT16-19 2.15258 2.15258 2.15258 ZT20-23 2.44141 2.44141 2.44141