condition mean min max ZT0-3 7.077707500000001 6.4677500000000006 7.687665000000001 ZT4-7 12.7487 12.7487 12.7487 ZT8-11 9.881615 9.881615 9.881615 ZT12-15 0 0 0 ZT16-19 10.13142 10.13142 10.13142 ZT20-23 12.76665 12.76665 12.76665