condition mean min max ZT0-3 1.5068166666666667 1.24946 1.8067 ZT4-7 0.6302745 0.6302745 0.6302745 ZT8-11 0.4871555 0.4871555 0.4871555 ZT12-15 0.9129637500000001 0.7862375 1.03969 ZT16-19 1.105505 1.105505 1.105505 ZT20-23 1.446195 1.446195 1.446195