condition mean min max ZT0-3 8.16266 8.16266 8.16266 ZT4-7 5.97039 5.97039 5.97039 ZT8-11 7.438955 7.438955 7.438955 ZT12-15 8.586475 8.586475 8.586475 ZT16-19 11.5502 11.5502 11.5502 ZT20-23 9.217055 9.217055 9.217055