condition mean min max ZT0-3 2.0644411666666667 0.644261 4.50741 ZT4-7 1.76557 1.76557 1.76557 ZT8-11 1.8689550000000001 1.8689550000000001 1.8689550000000001 ZT12-15 2.1031625 1.2254800000000001 2.980845 ZT16-19 1.35528 1.35528 1.35528 ZT20-23 1.001973 1.001973 1.001973