condition mean min max ZT0-3 21.866525000000003 18.707900000000002 25.02515 ZT4-7 13.6885 13.6885 13.6885 ZT8-11 20.41735 20.41735 20.41735 ZT12-15 0 0 0 ZT16-19 31.594949999999997 31.594949999999997 31.594949999999997 ZT20-23 20.1969 20.1969 20.1969