condition mean min max ZT0-3 19.537219 19.537219 19.537219 ZT4-7 22.448745 22.448745 22.448745 ZT8-11 18.803320499999998 18.803320499999998 18.803320499999998 ZT12-15 22.392751500000003 22.392751500000003 22.392751500000003 ZT16-19 19.968284500000003 19.968284500000003 19.968284500000003 ZT20-23 23.31193 23.31193 23.31193