condition mean min max ZT0-3 4.171305 4.171305 4.171305 ZT4-7 2.90425 2.90425 2.90425 ZT8-11 3.9512 3.9512 3.9512 ZT12-15 3.20324 3.20324 3.20324 ZT16-19 4.833209999999999 4.833209999999999 4.833209999999999 ZT20-23 4.228375 4.228375 4.228375