condition mean min max ZT0-3 3.438835 3.438835 3.438835 ZT4-7 4.35844 4.35844 4.35844 ZT8-11 5.9187899999999996 5.9187899999999996 5.9187899999999996 ZT12-15 15.815185 15.815185 15.815185 ZT16-19 11.4346 11.4346 11.4346 ZT20-23 20.77645 20.77645 20.77645