condition mean min max ZT0-3 3.092665 3.092665 3.092665 ZT4-7 2.86393 2.86393 2.86393 ZT8-11 1.60487 1.60487 1.60487 ZT12-15 2.7553549999999998 2.7553549999999998 2.7553549999999998 ZT16-19 3.40097 3.40097 3.40097 ZT20-23 3.41506 3.41506 3.41506