condition mean min max ZT0-3 6.1552050000000005 6.1552050000000005 6.1552050000000005 ZT4-7 4.68511 4.68511 4.68511 ZT8-11 4.8524899999999995 4.8524899999999995 4.8524899999999995 ZT12-15 5.052485 5.052485 5.052485 ZT16-19 7.347525 7.347525 7.347525 ZT20-23 5.804475 5.804475 5.804475