condition mean min max ZT0-3 6.914433333333333 5.00986 7.9548950000000005 ZT4-7 5.63656 5.63656 5.63656 ZT8-11 4.833819999999999 4.833819999999999 4.833819999999999 ZT12-15 9.6795075 6.957065 12.40195 ZT16-19 8.70629 8.70629 8.70629 ZT20-23 9.353909999999999 9.353909999999999 9.353909999999999