condition mean min max ZT0-3 2.85084 2.73916 2.96252 ZT4-7 3.10558 3.10558 3.10558 ZT8-11 2.469685 2.469685 2.469685 ZT12-15 0 0 0 ZT16-19 3.067465 3.067465 3.067465 ZT20-23 3.75671 3.75671 3.75671