condition mean min max ZT0-3 5.047935 4.231055 6.14114 ZT4-7 3.400975 3.400975 3.400975 ZT8-11 2.628375 2.628375 2.628375 ZT12-15 3.9498724999999997 3.3929799999999997 4.506765 ZT16-19 6.00159 6.00159 6.00159 ZT20-23 8.638495 8.638495 8.638495