condition mean min max ZT0-3 1.5997813333333333 0.858879 2.11661 ZT4-7 1.5583749999999998 1.5583749999999998 1.5583749999999998 ZT8-11 1.60707 1.60707 1.60707 ZT12-15 1.9344350000000001 1.75777 2.1111 ZT16-19 1.803535 1.803535 1.803535 ZT20-23 1.0171725 1.0171725 1.0171725