condition mean min max ZT0-3 2.9231 2.9231 2.9231 ZT4-7 2.2916 2.2916 2.2916 ZT8-11 1.9836749999999999 1.9836749999999999 1.9836749999999999 ZT12-15 2.446425 2.446425 2.446425 ZT16-19 3.277755 3.277755 3.277755 ZT20-23 2.6923399999999997 2.6923399999999997 2.6923399999999997