condition mean min max ZT0-3 2.381718333333333 1.988355 3.027525 ZT4-7 1.2681419999999999 1.2681419999999999 1.2681419999999999 ZT8-11 2.83597 2.83597 2.83597 ZT12-15 5.482442499999999 5.233445 5.73144 ZT16-19 6.1998999999999995 6.1998999999999995 6.1998999999999995 ZT20-23 5.40545 5.40545 5.40545