condition mean min max ZT0-3 1.712695 1.712695 1.712695 ZT4-7 0.9299854999999999 0.9299854999999999 0.9299854999999999 ZT8-11 0.777643 0.777643 0.777643 ZT12-15 1.70712 1.70712 1.70712 ZT16-19 3.7234949999999998 3.7234949999999998 3.7234949999999998 ZT20-23 2.66127 2.66127 2.66127