condition mean min max ZT0-3 7.644567 7.644567 7.644567 ZT4-7 8.478902999999999 8.478902999999999 8.478902999999999 ZT8-11 7.88448 7.88448 7.88448 ZT12-15 8.447 8.447 8.447 ZT16-19 8.623821 8.623821 8.623821 ZT20-23 7.6563479999999995 7.6563479999999995 7.6563479999999995