condition mean min max ZT0-3 1.400485 1.400485 1.400485 ZT4-7 0.394982 0.394982 0.394982 ZT8-11 0.367973 0.367973 0.367973 ZT12-15 0.661729 0.661729 0.661729 ZT16-19 0.738766 0.738766 0.738766 ZT20-23 1.1838005 1.1838005 1.1838005