condition mean min max ZT0-3 8.177535 8.177535 8.177535 ZT4-7 8.08652 8.08652 8.08652 ZT8-11 4.69375 4.69375 4.69375 ZT12-15 4.802785 4.802785 4.802785 ZT16-19 4.8683499999999995 4.8683499999999995 4.8683499999999995 ZT20-23 5.683365 5.683365 5.683365