condition mean min max ZT0-3 6.1775725 5.749175 6.60597 ZT4-7 4.256959999999999 4.256959999999999 4.256959999999999 ZT8-11 7.97349 7.97349 7.97349 ZT12-15 0 0 0 ZT16-19 7.718325 7.718325 7.718325 ZT20-23 7.205495 7.205495 7.205495