condition mean min max ZT0-3 3.3150566666666665 2.82601 3.681485 ZT4-7 3.367675 3.367675 3.367675 ZT8-11 6.669549999999999 6.669549999999999 6.669549999999999 ZT12-15 12.3235 11.86375 12.783249999999999 ZT16-19 10.751940000000001 10.751940000000001 10.751940000000001 ZT20-23 7.099795 7.099795 7.099795