condition mean min max ZT0-3 3.90669 3.90669 3.90669 ZT4-7 2.37147 2.37147 2.37147 ZT8-11 2.581905 2.581905 2.581905 ZT12-15 2.71604 2.71604 2.71604 ZT16-19 4.57596 4.57596 4.57596 ZT20-23 3.665375 3.665375 3.665375