condition mean min max ZT0-3 18.278475 15.0337 21.523249999999997 ZT4-7 16.5281 16.5281 16.5281 ZT8-11 21.093249999999998 21.093249999999998 21.093249999999998 ZT12-15 0 0 0 ZT16-19 22.423949999999998 22.423949999999998 22.423949999999998 ZT20-23 16.6697 16.6697 16.6697