condition mean min max ZT0-3 2.138095 2.07165 2.2045399999999997 ZT4-7 2.452895 2.452895 2.452895 ZT8-11 2.068925 2.068925 2.068925 ZT12-15 0 0 0 ZT16-19 2.5534850000000002 2.5534850000000002 2.5534850000000002 ZT20-23 2.8555599999999997 2.8555599999999997 2.8555599999999997