condition mean min max ZT0-3 1.9895999999999998 1.69357 2.28563 ZT4-7 2.00662 2.00662 2.00662 ZT8-11 2.31826 2.31826 2.31826 ZT12-15 0 0 0 ZT16-19 3.095395 3.095395 3.095395 ZT20-23 2.6870399999999997 2.6870399999999997 2.6870399999999997