condition mean min max ZT0-3 0.8917318333333333 0.34507 1.37323 ZT4-7 0.613826 0.613826 0.613826 ZT8-11 4.32691 4.32691 4.32691 ZT12-15 5.3033025 4.7126 5.894005 ZT16-19 6.074265 6.074265 6.074265 ZT20-23 3.2074249999999997 3.2074249999999997 3.2074249999999997