condition mean min max ZT0-3 8.959628384999998 8.590512618 9.328744151999999 ZT4-7 7.96245620425 7.9547366015 7.970175807 ZT8-11 8.82282751125 8.047494907 9.5981601155 ZT12-15 6.58215371725 6.1665345865 6.997772848 ZT16-19 3.7673194805000003 3.5423617564999996 3.9922772045000006 ZT20-23 3.60296302 3.3237093255 3.8822167145