condition mean min max ZT0-3 2.333425 2.333425 2.333425 ZT4-7 1.8483399999999999 1.8483399999999999 1.8483399999999999 ZT8-11 1.872195 1.872195 1.872195 ZT12-15 2.203175 2.203175 2.203175 ZT16-19 3.1039399999999997 3.1039399999999997 3.1039399999999997 ZT20-23 2.9582550000000003 2.9582550000000003 2.9582550000000003