condition mean min max ZT0-3 6.648975 5.251435 8.046515 ZT4-7 8.053745 8.053745 8.053745 ZT8-11 33.076100000000004 33.076100000000004 33.076100000000004 ZT12-15 0 0 0 ZT16-19 27.166449999999998 27.166449999999998 27.166449999999998 ZT20-23 15.1095 15.1095 15.1095