condition mean min max ZT0-3 6.317785 5.96776 6.667809999999999 ZT4-7 4.140555 4.140555 4.140555 ZT8-11 3.67321 3.67321 3.67321 ZT12-15 0 0 0 ZT16-19 7.09902 7.09902 7.09902 ZT20-23 8.177325 8.177325 8.177325