condition mean min max ZT0-3 8.502943333333334 7.55916 9.43486 ZT4-7 5.84171 5.84171 5.84171 ZT8-11 4.664485 4.664485 4.664485 ZT12-15 6.5481675 4.68703 8.409305 ZT16-19 5.31583 5.31583 5.31583 ZT20-23 7.832715 7.832715 7.832715