condition mean min max ZT0-3 3.681385 3.099215 4.263555 ZT4-7 4.4339949999999995 4.4339949999999995 4.4339949999999995 ZT8-11 5.37716 5.37716 5.37716 ZT12-15 0 0 0 ZT16-19 5.4958849999999995 5.4958849999999995 5.4958849999999995 ZT20-23 5.68433 5.68433 5.68433