condition mean min max ZT0-3 3.04317 3.04317 3.04317 ZT4-7 3.13632 3.13632 3.13632 ZT8-11 1.906435 1.906435 1.906435 ZT12-15 2.66725 2.66725 2.66725 ZT16-19 3.5078050000000003 3.5078050000000003 3.5078050000000003 ZT20-23 3.759255 3.759255 3.759255