condition mean min max ZT0-3 3.314255 3.314255 3.314255 ZT4-7 2.120985 2.120985 2.120985 ZT8-11 1.87325 1.87325 1.87325 ZT12-15 4.390005 4.390005 4.390005 ZT16-19 22.64062 22.64062 22.64062 ZT20-23 6.20473 6.20473 6.20473