condition mean min max ZT0-3 6.992416666666666 6.355475 7.93506 ZT4-7 6.734475 6.734475 6.734475 ZT8-11 6.105230000000001 6.105230000000001 6.105230000000001 ZT12-15 10.12507 9.553239999999999 10.6969 ZT16-19 9.639050000000001 9.639050000000001 9.639050000000001 ZT20-23 9.07785 9.07785 9.07785