condition mean min max ZT0-3 1.7133525 1.566595 1.8601100000000002 ZT4-7 0.9599395 0.9599395 0.9599395 ZT8-11 3.04892 3.04892 3.04892 ZT12-15 0 0 0 ZT16-19 6.435454999999999 6.435454999999999 6.435454999999999 ZT20-23 3.85959 3.85959 3.85959