condition mean min max ZT0-3 6.23803 6.23803 6.23803 ZT4-7 3.698965 3.698965 3.698965 ZT8-11 3.8073750000000004 3.8073750000000004 3.8073750000000004 ZT12-15 4.992635 4.992635 4.992635 ZT16-19 5.409535 5.409535 5.409535 ZT20-23 5.191355 5.191355 5.191355