condition mean min max ZT0-3 4.140826666666666 2.854905 4.8089949999999995 ZT4-7 2.267535 2.267535 2.267535 ZT8-11 2.798145 2.798145 2.798145 ZT12-15 4.585675 2.37108 6.800269999999999 ZT16-19 3.56328 3.56328 3.56328 ZT20-23 3.5462975 3.5462975 3.5462975