condition mean min max ZT0-3 2.5565725 1.454685 3.6584600000000003 ZT4-7 4.7722500000000005 4.7722500000000005 4.7722500000000005 ZT8-11 7.1489899999999995 7.1489899999999995 7.1489899999999995 ZT12-15 6.9597875 6.59481 7.324765 ZT16-19 3.4717366666666667 2.505063333333333 4.43841 ZT20-23 0 0 0