condition mean min max ZT0-3 7.4047525 6.8739799999999995 7.935525 ZT4-7 7.475210000000001 7.475210000000001 7.475210000000001 ZT8-11 10.682549999999999 10.682549999999999 10.682549999999999 ZT12-15 0 0 0 ZT16-19 12.565000000000001 12.565000000000001 12.565000000000001 ZT20-23 10.386299999999999 10.386299999999999 10.386299999999999