condition mean min max ZT0-3 10.044158 10.044158 10.044158 ZT4-7 8.910391 8.910391 8.910391 ZT8-11 8.6378695 8.6378695 8.6378695 ZT12-15 8.91737 8.91737 8.91737 ZT16-19 9.390558500000001 9.390558500000001 9.390558500000001 ZT20-23 8.872114 8.872114 8.872114