condition mean min max ZT0-3 1.081375 1.081375 1.081375 ZT4-7 5.039155 5.039155 5.039155 ZT8-11 6.856535 6.856535 6.856535 ZT12-15 5.4247499999999995 5.4247499999999995 5.4247499999999995 ZT16-19 2.191865 2.191865 2.191865 ZT20-23 3.84441 3.84441 3.84441