condition mean min max ZT0-3 3.178085 2.1499800000000002 3.8121 ZT4-7 2.2714999999999996 2.2714999999999996 2.2714999999999996 ZT8-11 2.289815 2.289815 2.289815 ZT12-15 2.4895475000000005 2.1339 2.8451950000000004 ZT16-19 2.228645 2.228645 2.228645 ZT20-23 5.325585 5.325585 5.325585