condition mean min max ZT0-3 1.3477316666666666 1.24867 1.45725 ZT4-7 1.3939 1.3939 1.3939 ZT8-11 1.236535 1.236535 1.236535 ZT12-15 0.97505625 0.8563875 1.093725 ZT16-19 1.55555 1.55555 1.55555 ZT20-23 1.56088 1.56088 1.56088