condition mean min max ZT0-3 6.098845 5.043825 7.99138 ZT4-7 4.84463 4.84463 4.84463 ZT8-11 3.056255 3.056255 3.056255 ZT12-15 4.6278325 4.350135 4.90553 ZT16-19 3.277155 3.277155 3.277155 ZT20-23 4.67532 4.67532 4.67532